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4ee9c684 | 1 | /* SSA Dominator optimizations for trees |
c46a7a9f | 2 | Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. |
4ee9c684 | 3 | Contributed by Diego Novillo <dnovillo@redhat.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to | |
19 | the Free Software Foundation, 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
21 | ||
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "flags.h" | |
28 | #include "rtl.h" | |
29 | #include "tm_p.h" | |
30 | #include "ggc.h" | |
31 | #include "basic-block.h" | |
388d1fc1 | 32 | #include "cfgloop.h" |
4ee9c684 | 33 | #include "output.h" |
34 | #include "errors.h" | |
35 | #include "expr.h" | |
36 | #include "function.h" | |
37 | #include "diagnostic.h" | |
38 | #include "timevar.h" | |
39 | #include "tree-dump.h" | |
40 | #include "tree-flow.h" | |
41 | #include "domwalk.h" | |
42 | #include "real.h" | |
43 | #include "tree-pass.h" | |
7d564439 | 44 | #include "tree-ssa-propagate.h" |
4ee9c684 | 45 | #include "langhooks.h" |
46 | ||
47 | /* This file implements optimizations on the dominator tree. */ | |
48 | ||
2f0993e7 | 49 | |
50 | /* Structure for recording edge equivalences as well as any pending | |
51 | edge redirections during the dominator optimizer. | |
52 | ||
53 | Computing and storing the edge equivalences instead of creating | |
54 | them on-demand can save significant amounts of time, particularly | |
55 | for pathological cases involving switch statements. | |
56 | ||
57 | These structures live for a single iteration of the dominator | |
58 | optimizer in the edge's AUX field. At the end of an iteration we | |
59 | free each of these structures and update the AUX field to point | |
60 | to any requested redirection target (the code for updating the | |
61 | CFG and SSA graph for edge redirection expects redirection edge | |
62 | targets to be in the AUX field for each edge. */ | |
63 | ||
64 | struct edge_info | |
65 | { | |
66 | /* If this edge creates a simple equivalence, the LHS and RHS of | |
67 | the equivalence will be stored here. */ | |
68 | tree lhs; | |
69 | tree rhs; | |
70 | ||
71 | /* Traversing an edge may also indicate one or more particular conditions | |
72 | are true or false. The number of recorded conditions can vary, but | |
73 | can be determined by the condition's code. So we have an array | |
74 | and its maximum index rather than use a varray. */ | |
75 | tree *cond_equivalences; | |
76 | unsigned int max_cond_equivalences; | |
77 | ||
78 | /* If we can thread this edge this field records the new target. */ | |
79 | edge redirection_target; | |
80 | }; | |
81 | ||
82 | ||
4ee9c684 | 83 | /* Hash table with expressions made available during the renaming process. |
84 | When an assignment of the form X_i = EXPR is found, the statement is | |
85 | stored in this table. If the same expression EXPR is later found on the | |
86 | RHS of another statement, it is replaced with X_i (thus performing | |
87 | global redundancy elimination). Similarly as we pass through conditionals | |
88 | we record the conditional itself as having either a true or false value | |
89 | in this table. */ | |
90 | static htab_t avail_exprs; | |
91 | ||
9c629f0e | 92 | /* Stack of available expressions in AVAIL_EXPRs. Each block pushes any |
93 | expressions it enters into the hash table along with a marker entry | |
73645111 | 94 | (null). When we finish processing the block, we pop off entries and |
9c629f0e | 95 | remove the expressions from the global hash table until we hit the |
96 | marker. */ | |
046bfc77 | 97 | static VEC(tree,heap) *avail_exprs_stack; |
9c629f0e | 98 | |
a721131d | 99 | /* Stack of statements we need to rescan during finalization for newly |
100 | exposed variables. | |
101 | ||
102 | Statement rescanning must occur after the current block's available | |
103 | expressions are removed from AVAIL_EXPRS. Else we may change the | |
104 | hash code for an expression and be unable to find/remove it from | |
105 | AVAIL_EXPRS. */ | |
046bfc77 | 106 | static VEC(tree,heap) *stmts_to_rescan; |
a721131d | 107 | |
4ee9c684 | 108 | /* Structure for entries in the expression hash table. |
109 | ||
110 | This requires more memory for the hash table entries, but allows us | |
111 | to avoid creating silly tree nodes and annotations for conditionals, | |
112 | eliminates 2 global hash tables and two block local varrays. | |
113 | ||
114 | It also allows us to reduce the number of hash table lookups we | |
115 | have to perform in lookup_avail_expr and finally it allows us to | |
116 | significantly reduce the number of calls into the hashing routine | |
117 | itself. */ | |
a8046f60 | 118 | |
4ee9c684 | 119 | struct expr_hash_elt |
120 | { | |
121 | /* The value (lhs) of this expression. */ | |
122 | tree lhs; | |
123 | ||
124 | /* The expression (rhs) we want to record. */ | |
125 | tree rhs; | |
126 | ||
b66731e8 | 127 | /* The stmt pointer if this element corresponds to a statement. */ |
128 | tree stmt; | |
4ee9c684 | 129 | |
130 | /* The hash value for RHS/ann. */ | |
131 | hashval_t hash; | |
132 | }; | |
133 | ||
da43203c | 134 | /* Stack of dest,src pairs that need to be restored during finalization. |
135 | ||
136 | A NULL entry is used to mark the end of pairs which need to be | |
137 | restored during finalization of this block. */ | |
046bfc77 | 138 | static VEC(tree,heap) *const_and_copies_stack; |
da43203c | 139 | |
4ee9c684 | 140 | /* Bitmap of SSA_NAMEs known to have a nonzero value, even if we do not |
141 | know their exact value. */ | |
142 | static bitmap nonzero_vars; | |
143 | ||
180d0339 | 144 | /* Stack of SSA_NAMEs which need their NONZERO_VARS property cleared |
145 | when the current block is finalized. | |
146 | ||
147 | A NULL entry is used to mark the end of names needing their | |
148 | entry in NONZERO_VARS cleared during finalization of this block. */ | |
046bfc77 | 149 | static VEC(tree,heap) *nonzero_vars_stack; |
180d0339 | 150 | |
4ee9c684 | 151 | /* Track whether or not we have changed the control flow graph. */ |
152 | static bool cfg_altered; | |
153 | ||
35c15734 | 154 | /* Bitmap of blocks that have had EH statements cleaned. We should |
0870fd6e | 155 | remove their dead edges eventually. */ |
35c15734 | 156 | static bitmap need_eh_cleanup; |
157 | ||
4ee9c684 | 158 | /* Statistics for dominator optimizations. */ |
159 | struct opt_stats_d | |
160 | { | |
161 | long num_stmts; | |
162 | long num_exprs_considered; | |
163 | long num_re; | |
88dbf20f | 164 | long num_const_prop; |
165 | long num_copy_prop; | |
4ee9c684 | 166 | }; |
167 | ||
d0d897b6 | 168 | static struct opt_stats_d opt_stats; |
169 | ||
4ee9c684 | 170 | /* Value range propagation record. Each time we encounter a conditional |
171 | of the form SSA_NAME COND CONST we create a new vrp_element to record | |
172 | how the condition affects the possible values SSA_NAME may have. | |
173 | ||
822e391f | 174 | Each record contains the condition tested (COND), and the range of |
4ee9c684 | 175 | values the variable may legitimately have if COND is true. Note the |
176 | range of values may be a smaller range than COND specifies if we have | |
177 | recorded other ranges for this variable. Each record also contains the | |
178 | block in which the range was recorded for invalidation purposes. | |
179 | ||
180 | Note that the current known range is computed lazily. This allows us | |
181 | to avoid the overhead of computing ranges which are never queried. | |
182 | ||
183 | When we encounter a conditional, we look for records which constrain | |
184 | the SSA_NAME used in the condition. In some cases those records allow | |
185 | us to determine the condition's result at compile time. In other cases | |
186 | they may allow us to simplify the condition. | |
187 | ||
188 | We also use value ranges to do things like transform signed div/mod | |
189 | operations into unsigned div/mod or to simplify ABS_EXPRs. | |
190 | ||
191 | Simple experiments have shown these optimizations to not be all that | |
192 | useful on switch statements (much to my surprise). So switch statement | |
193 | optimizations are not performed. | |
194 | ||
195 | Note carefully we do not propagate information through each statement | |
0c6d8c36 | 196 | in the block. i.e., if we know variable X has a value defined of |
4ee9c684 | 197 | [0, 25] and we encounter Y = X + 1, we do not track a value range |
198 | for Y (which would be [1, 26] if we cared). Similarly we do not | |
199 | constrain values as we encounter narrowing typecasts, etc. */ | |
200 | ||
201 | struct vrp_element | |
202 | { | |
203 | /* The highest and lowest values the variable in COND may contain when | |
204 | COND is true. Note this may not necessarily be the same values | |
205 | tested by COND if the same variable was used in earlier conditionals. | |
206 | ||
207 | Note this is computed lazily and thus can be NULL indicating that | |
208 | the values have not been computed yet. */ | |
209 | tree low; | |
210 | tree high; | |
211 | ||
212 | /* The actual conditional we recorded. This is needed since we compute | |
213 | ranges lazily. */ | |
214 | tree cond; | |
215 | ||
216 | /* The basic block where this record was created. We use this to determine | |
217 | when to remove records. */ | |
218 | basic_block bb; | |
219 | }; | |
220 | ||
d0d897b6 | 221 | /* A hash table holding value range records (VRP_ELEMENTs) for a given |
222 | SSA_NAME. We used to use a varray indexed by SSA_NAME_VERSION, but | |
223 | that gets awful wasteful, particularly since the density objects | |
224 | with useful information is very low. */ | |
225 | static htab_t vrp_data; | |
226 | ||
227 | /* An entry in the VRP_DATA hash table. We record the variable and a | |
dac49aa5 | 228 | varray of VRP_ELEMENT records associated with that variable. */ |
d0d897b6 | 229 | struct vrp_hash_elt |
230 | { | |
231 | tree var; | |
232 | varray_type records; | |
233 | }; | |
4ee9c684 | 234 | |
180d0339 | 235 | /* Array of variables which have their values constrained by operations |
236 | in this basic block. We use this during finalization to know | |
237 | which variables need their VRP data updated. */ | |
4ee9c684 | 238 | |
0975351b | 239 | /* Stack of SSA_NAMEs which had their values constrained by operations |
180d0339 | 240 | in this basic block. During finalization of this block we use this |
241 | list to determine which variables need their VRP data updated. | |
242 | ||
243 | A NULL entry marks the end of the SSA_NAMEs associated with this block. */ | |
046bfc77 | 244 | static VEC(tree,heap) *vrp_variables_stack; |
4ee9c684 | 245 | |
246 | struct eq_expr_value | |
247 | { | |
248 | tree src; | |
249 | tree dst; | |
250 | }; | |
251 | ||
252 | /* Local functions. */ | |
253 | static void optimize_stmt (struct dom_walk_data *, | |
254 | basic_block bb, | |
255 | block_stmt_iterator); | |
9c629f0e | 256 | static tree lookup_avail_expr (tree, bool); |
d0d897b6 | 257 | static hashval_t vrp_hash (const void *); |
258 | static int vrp_eq (const void *, const void *); | |
4ee9c684 | 259 | static hashval_t avail_expr_hash (const void *); |
23ace16d | 260 | static hashval_t real_avail_expr_hash (const void *); |
4ee9c684 | 261 | static int avail_expr_eq (const void *, const void *); |
262 | static void htab_statistics (FILE *, htab_t); | |
9c629f0e | 263 | static void record_cond (tree, tree); |
da43203c | 264 | static void record_const_or_copy (tree, tree); |
265 | static void record_equality (tree, tree); | |
9c629f0e | 266 | static tree update_rhs_and_lookup_avail_expr (tree, tree, bool); |
4ee9c684 | 267 | static tree simplify_rhs_and_lookup_avail_expr (struct dom_walk_data *, |
ac4bd4cc | 268 | tree, int); |
9c629f0e | 269 | static tree simplify_cond_and_lookup_avail_expr (tree, stmt_ann_t, int); |
270 | static tree simplify_switch_and_lookup_avail_expr (tree, int); | |
4ee9c684 | 271 | static tree find_equivalent_equality_comparison (tree); |
180d0339 | 272 | static void record_range (tree, basic_block); |
4ee9c684 | 273 | static bool extract_range_from_cond (tree, tree *, tree *, int *); |
2f0993e7 | 274 | static void record_equivalences_from_phis (basic_block); |
275 | static void record_equivalences_from_incoming_edge (basic_block); | |
4ee9c684 | 276 | static bool eliminate_redundant_computations (struct dom_walk_data *, |
277 | tree, stmt_ann_t); | |
180d0339 | 278 | static void record_equivalences_from_stmt (tree, int, stmt_ann_t); |
4ee9c684 | 279 | static void thread_across_edge (struct dom_walk_data *, edge); |
280 | static void dom_opt_finalize_block (struct dom_walk_data *, basic_block); | |
4ee9c684 | 281 | static void dom_opt_initialize_block (struct dom_walk_data *, basic_block); |
2f0993e7 | 282 | static void propagate_to_outgoing_edges (struct dom_walk_data *, basic_block); |
9c629f0e | 283 | static void remove_local_expressions_from_table (void); |
da43203c | 284 | static void restore_vars_to_original_value (void); |
c0735efa | 285 | static edge single_incoming_edge_ignoring_loop_edges (basic_block); |
180d0339 | 286 | static void restore_nonzero_vars_to_original_value (void); |
78f29aa3 | 287 | static inline bool unsafe_associative_fp_binop (tree); |
4ee9c684 | 288 | |
88dbf20f | 289 | |
4ee9c684 | 290 | /* Local version of fold that doesn't introduce cruft. */ |
291 | ||
292 | static tree | |
293 | local_fold (tree t) | |
294 | { | |
295 | t = fold (t); | |
296 | ||
297 | /* Strip away useless type conversions. Both the NON_LVALUE_EXPR that | |
298 | may have been added by fold, and "useless" type conversions that might | |
299 | now be apparent due to propagation. */ | |
4ee9c684 | 300 | STRIP_USELESS_TYPE_CONVERSION (t); |
301 | ||
302 | return t; | |
303 | } | |
304 | ||
2f0993e7 | 305 | /* Allocate an EDGE_INFO for edge E and attach it to E. |
306 | Return the new EDGE_INFO structure. */ | |
307 | ||
308 | static struct edge_info * | |
309 | allocate_edge_info (edge e) | |
310 | { | |
311 | struct edge_info *edge_info; | |
312 | ||
313 | edge_info = xcalloc (1, sizeof (struct edge_info)); | |
314 | ||
315 | e->aux = edge_info; | |
316 | return edge_info; | |
317 | } | |
318 | ||
319 | /* Free all EDGE_INFO structures associated with edges in the CFG. | |
640e9781 | 320 | If a particular edge can be threaded, copy the redirection |
2f0993e7 | 321 | target from the EDGE_INFO structure into the edge's AUX field |
322 | as required by code to update the CFG and SSA graph for | |
323 | jump threading. */ | |
324 | ||
325 | static void | |
326 | free_all_edge_infos (void) | |
327 | { | |
328 | basic_block bb; | |
329 | edge_iterator ei; | |
330 | edge e; | |
331 | ||
332 | FOR_EACH_BB (bb) | |
333 | { | |
334 | FOR_EACH_EDGE (e, ei, bb->preds) | |
335 | { | |
336 | struct edge_info *edge_info = e->aux; | |
337 | ||
338 | if (edge_info) | |
339 | { | |
340 | e->aux = edge_info->redirection_target; | |
341 | if (edge_info->cond_equivalences) | |
342 | free (edge_info->cond_equivalences); | |
343 | free (edge_info); | |
344 | } | |
345 | } | |
346 | } | |
347 | } | |
348 | ||
4ee9c684 | 349 | /* Jump threading, redundancy elimination and const/copy propagation. |
350 | ||
4ee9c684 | 351 | This pass may expose new symbols that need to be renamed into SSA. For |
352 | every new symbol exposed, its corresponding bit will be set in | |
591c2a30 | 353 | VARS_TO_RENAME. */ |
4ee9c684 | 354 | |
355 | static void | |
356 | tree_ssa_dominator_optimize (void) | |
357 | { | |
4ee9c684 | 358 | struct dom_walk_data walk_data; |
359 | unsigned int i; | |
388d1fc1 | 360 | struct loops loops_info; |
4ee9c684 | 361 | |
03ec6c0e | 362 | memset (&opt_stats, 0, sizeof (opt_stats)); |
363 | ||
4ee9c684 | 364 | /* Create our hash tables. */ |
23ace16d | 365 | avail_exprs = htab_create (1024, real_avail_expr_hash, avail_expr_eq, free); |
d0d897b6 | 366 | vrp_data = htab_create (ceil_log2 (num_ssa_names), vrp_hash, vrp_eq, free); |
046bfc77 | 367 | avail_exprs_stack = VEC_alloc (tree, heap, 20); |
046bfc77 | 368 | const_and_copies_stack = VEC_alloc (tree, heap, 20); |
369 | nonzero_vars_stack = VEC_alloc (tree, heap, 20); | |
370 | vrp_variables_stack = VEC_alloc (tree, heap, 20); | |
371 | stmts_to_rescan = VEC_alloc (tree, heap, 20); | |
27335ffd | 372 | nonzero_vars = BITMAP_ALLOC (NULL); |
373 | need_eh_cleanup = BITMAP_ALLOC (NULL); | |
4ee9c684 | 374 | |
375 | /* Setup callbacks for the generic dominator tree walker. */ | |
376 | walk_data.walk_stmts_backward = false; | |
377 | walk_data.dom_direction = CDI_DOMINATORS; | |
180d0339 | 378 | walk_data.initialize_block_local_data = NULL; |
4ee9c684 | 379 | walk_data.before_dom_children_before_stmts = dom_opt_initialize_block; |
380 | walk_data.before_dom_children_walk_stmts = optimize_stmt; | |
2f0993e7 | 381 | walk_data.before_dom_children_after_stmts = propagate_to_outgoing_edges; |
4ee9c684 | 382 | walk_data.after_dom_children_before_stmts = NULL; |
383 | walk_data.after_dom_children_walk_stmts = NULL; | |
384 | walk_data.after_dom_children_after_stmts = dom_opt_finalize_block; | |
385 | /* Right now we only attach a dummy COND_EXPR to the global data pointer. | |
386 | When we attach more stuff we'll need to fill this out with a real | |
387 | structure. */ | |
388 | walk_data.global_data = NULL; | |
180d0339 | 389 | walk_data.block_local_data_size = 0; |
88dbf20f | 390 | walk_data.interesting_blocks = NULL; |
4ee9c684 | 391 | |
392 | /* Now initialize the dominator walker. */ | |
393 | init_walk_dominator_tree (&walk_data); | |
394 | ||
4ee9c684 | 395 | calculate_dominance_info (CDI_DOMINATORS); |
396 | ||
388d1fc1 | 397 | /* We need to know which edges exit loops so that we can |
398 | aggressively thread through loop headers to an exit | |
399 | edge. */ | |
400 | flow_loops_find (&loops_info); | |
401 | mark_loop_exit_edges (&loops_info); | |
402 | flow_loops_free (&loops_info); | |
403 | ||
404 | /* Clean up the CFG so that any forwarder blocks created by loop | |
405 | canonicalization are removed. */ | |
406 | cleanup_tree_cfg (); | |
8171a1dd | 407 | calculate_dominance_info (CDI_DOMINATORS); |
388d1fc1 | 408 | |
4ee9c684 | 409 | /* If we prove certain blocks are unreachable, then we want to |
410 | repeat the dominator optimization process as PHI nodes may | |
411 | have turned into copies which allows better propagation of | |
412 | values. So we repeat until we do not identify any new unreachable | |
413 | blocks. */ | |
414 | do | |
415 | { | |
416 | /* Optimize the dominator tree. */ | |
417 | cfg_altered = false; | |
418 | ||
388d1fc1 | 419 | /* We need accurate information regarding back edges in the CFG |
420 | for jump threading. */ | |
421 | mark_dfs_back_edges (); | |
422 | ||
4ee9c684 | 423 | /* Recursively walk the dominator tree optimizing statements. */ |
424 | walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); | |
425 | ||
a8046f60 | 426 | /* If we exposed any new variables, go ahead and put them into |
427 | SSA form now, before we handle jump threading. This simplifies | |
428 | interactions between rewriting of _DECL nodes into SSA form | |
429 | and rewriting SSA_NAME nodes into SSA form after block | |
430 | duplication and CFG manipulation. */ | |
88dbf20f | 431 | update_ssa (TODO_update_ssa); |
4ee9c684 | 432 | |
2f0993e7 | 433 | free_all_edge_infos (); |
434 | ||
22aa74c4 | 435 | { |
0638045e | 436 | block_stmt_iterator bsi; |
437 | basic_block bb; | |
438 | FOR_EACH_BB (bb) | |
22aa74c4 | 439 | { |
0638045e | 440 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) |
441 | { | |
442 | update_stmt_if_modified (bsi_stmt (bsi)); | |
443 | } | |
22aa74c4 | 444 | } |
445 | } | |
0638045e | 446 | |
a8046f60 | 447 | /* Thread jumps, creating duplicate blocks as needed. */ |
1233bd09 | 448 | cfg_altered |= thread_through_all_blocks (); |
4ee9c684 | 449 | |
a8046f60 | 450 | /* Removal of statements may make some EH edges dead. Purge |
451 | such edges from the CFG as needed. */ | |
604efc01 | 452 | if (!bitmap_empty_p (need_eh_cleanup)) |
35c15734 | 453 | { |
a8046f60 | 454 | cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup); |
35c15734 | 455 | bitmap_zero (need_eh_cleanup); |
456 | } | |
457 | ||
c32258fb | 458 | if (cfg_altered) |
388d1fc1 | 459 | free_dominance_info (CDI_DOMINATORS); |
460 | ||
a01d0a8b | 461 | cfg_altered = cleanup_tree_cfg (); |
388d1fc1 | 462 | |
463 | if (rediscover_loops_after_threading) | |
464 | { | |
465 | /* Rerun basic loop analysis to discover any newly | |
466 | created loops and update the set of exit edges. */ | |
467 | rediscover_loops_after_threading = false; | |
468 | flow_loops_find (&loops_info); | |
469 | mark_loop_exit_edges (&loops_info); | |
470 | flow_loops_free (&loops_info); | |
471 | ||
472 | /* Remove any forwarder blocks inserted by loop | |
473 | header canonicalization. */ | |
474 | cleanup_tree_cfg (); | |
475 | } | |
476 | ||
a8046f60 | 477 | calculate_dominance_info (CDI_DOMINATORS); |
4ee9c684 | 478 | |
095dcfa3 | 479 | update_ssa (TODO_update_ssa); |
4ee9c684 | 480 | |
4ee9c684 | 481 | /* Reinitialize the various tables. */ |
482 | bitmap_clear (nonzero_vars); | |
483 | htab_empty (avail_exprs); | |
d0d897b6 | 484 | htab_empty (vrp_data); |
4ee9c684 | 485 | |
7414901f | 486 | /* Finally, remove everything except invariants in SSA_NAME_VALUE. |
487 | ||
488 | This must be done before we iterate as we might have a | |
489 | reference to an SSA_NAME which was removed by the call to | |
77d7fee0 | 490 | update_ssa. |
7414901f | 491 | |
492 | Long term we will be able to let everything in SSA_NAME_VALUE | |
493 | persist. However, for now, we know this is the safe thing to do. */ | |
494 | for (i = 0; i < num_ssa_names; i++) | |
495 | { | |
496 | tree name = ssa_name (i); | |
497 | tree value; | |
498 | ||
499 | if (!name) | |
500 | continue; | |
501 | ||
502 | value = SSA_NAME_VALUE (name); | |
503 | if (value && !is_gimple_min_invariant (value)) | |
504 | SSA_NAME_VALUE (name) = NULL; | |
505 | } | |
4ee9c684 | 506 | } |
523a88b0 | 507 | while (optimize > 1 && cfg_altered); |
4ee9c684 | 508 | |
4ee9c684 | 509 | /* Debugging dumps. */ |
510 | if (dump_file && (dump_flags & TDF_STATS)) | |
511 | dump_dominator_optimization_stats (dump_file); | |
512 | ||
2c763ed4 | 513 | /* We emptied the hash table earlier, now delete it completely. */ |
4ee9c684 | 514 | htab_delete (avail_exprs); |
d0d897b6 | 515 | htab_delete (vrp_data); |
4ee9c684 | 516 | |
365db11e | 517 | /* It is not necessary to clear CURRDEFS, REDIRECTION_EDGES, VRP_DATA, |
4ee9c684 | 518 | CONST_AND_COPIES, and NONZERO_VARS as they all get cleared at the bottom |
519 | of the do-while loop above. */ | |
520 | ||
521 | /* And finalize the dominator walker. */ | |
522 | fini_walk_dominator_tree (&walk_data); | |
a8ddfbad | 523 | |
dac49aa5 | 524 | /* Free nonzero_vars. */ |
27335ffd | 525 | BITMAP_FREE (nonzero_vars); |
526 | BITMAP_FREE (need_eh_cleanup); | |
486b57c7 | 527 | |
046bfc77 | 528 | VEC_free (tree, heap, avail_exprs_stack); |
529 | VEC_free (tree, heap, const_and_copies_stack); | |
530 | VEC_free (tree, heap, nonzero_vars_stack); | |
531 | VEC_free (tree, heap, vrp_variables_stack); | |
532 | VEC_free (tree, heap, stmts_to_rescan); | |
4ee9c684 | 533 | } |
534 | ||
535 | static bool | |
536 | gate_dominator (void) | |
537 | { | |
538 | return flag_tree_dom != 0; | |
539 | } | |
540 | ||
541 | struct tree_opt_pass pass_dominator = | |
542 | { | |
543 | "dom", /* name */ | |
544 | gate_dominator, /* gate */ | |
545 | tree_ssa_dominator_optimize, /* execute */ | |
546 | NULL, /* sub */ | |
547 | NULL, /* next */ | |
548 | 0, /* static_pass_number */ | |
549 | TV_TREE_SSA_DOMINATOR_OPTS, /* tv_id */ | |
f45a1ca1 | 550 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ |
4ee9c684 | 551 | 0, /* properties_provided */ |
552 | 0, /* properties_destroyed */ | |
553 | 0, /* todo_flags_start */ | |
88dbf20f | 554 | TODO_dump_func |
555 | | TODO_update_ssa | |
0f9005dd | 556 | | TODO_verify_ssa, /* todo_flags_finish */ |
557 | 0 /* letter */ | |
4ee9c684 | 558 | }; |
559 | ||
560 | ||
a01d0a8b | 561 | /* We are exiting E->src, see if E->dest ends with a conditional |
562 | jump which has a known value when reached via E. | |
563 | ||
564 | Special care is necessary if E is a back edge in the CFG as we | |
565 | will have already recorded equivalences for E->dest into our | |
566 | various tables, including the result of the conditional at | |
567 | the end of E->dest. Threading opportunities are severely | |
568 | limited in that case to avoid short-circuiting the loop | |
569 | incorrectly. | |
570 | ||
571 | Note it is quite common for the first block inside a loop to | |
572 | end with a conditional which is either always true or always | |
573 | false when reached via the loop backedge. Thus we do not want | |
574 | to blindly disable threading across a loop backedge. */ | |
4ee9c684 | 575 | |
576 | static void | |
577 | thread_across_edge (struct dom_walk_data *walk_data, edge e) | |
578 | { | |
4ee9c684 | 579 | block_stmt_iterator bsi; |
580 | tree stmt = NULL; | |
581 | tree phi; | |
582 | ||
a01d0a8b | 583 | /* If E->dest does not end with a conditional, then there is |
584 | nothing to do. */ | |
585 | bsi = bsi_last (e->dest); | |
586 | if (bsi_end_p (bsi) | |
587 | || ! bsi_stmt (bsi) | |
588 | || (TREE_CODE (bsi_stmt (bsi)) != COND_EXPR | |
589 | && TREE_CODE (bsi_stmt (bsi)) != GOTO_EXPR | |
590 | && TREE_CODE (bsi_stmt (bsi)) != SWITCH_EXPR)) | |
591 | return; | |
592 | ||
593 | /* The basic idea here is to use whatever knowledge we have | |
594 | from our dominator walk to simplify statements in E->dest, | |
595 | with the ultimate goal being to simplify the conditional | |
596 | at the end of E->dest. | |
597 | ||
598 | Note that we must undo any changes we make to the underlying | |
599 | statements as the simplifications we are making are control | |
600 | flow sensitive (ie, the simplifications are valid when we | |
601 | traverse E, but may not be valid on other paths to E->dest. */ | |
602 | ||
603 | /* Each PHI creates a temporary equivalence, record them. Again | |
604 | these are context sensitive equivalences and will be removed | |
605 | by our caller. */ | |
04f8eea3 | 606 | for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi)) |
4ee9c684 | 607 | { |
56004dc5 | 608 | tree src = PHI_ARG_DEF_FROM_EDGE (phi, e); |
4ee9c684 | 609 | tree dst = PHI_RESULT (phi); |
a7ab67e0 | 610 | |
611 | /* If the desired argument is not the same as this PHI's result | |
a01d0a8b | 612 | and it is set by a PHI in E->dest, then we can not thread |
613 | through E->dest. */ | |
a7ab67e0 | 614 | if (src != dst |
615 | && TREE_CODE (src) == SSA_NAME | |
616 | && TREE_CODE (SSA_NAME_DEF_STMT (src)) == PHI_NODE | |
617 | && bb_for_stmt (SSA_NAME_DEF_STMT (src)) == e->dest) | |
618 | return; | |
619 | ||
da43203c | 620 | record_const_or_copy (dst, src); |
4ee9c684 | 621 | } |
622 | ||
a01d0a8b | 623 | /* Try to simplify each statement in E->dest, ultimately leading to |
624 | a simplification of the COND_EXPR at the end of E->dest. | |
625 | ||
626 | We might consider marking just those statements which ultimately | |
627 | feed the COND_EXPR. It's not clear if the overhead of bookkeeping | |
628 | would be recovered by trying to simplify fewer statements. | |
629 | ||
630 | If we are able to simplify a statement into the form | |
631 | SSA_NAME = (SSA_NAME | gimple invariant), then we can record | |
632 | a context sensitive equivalency which may help us simplify | |
633 | later statements in E->dest. | |
634 | ||
635 | Failure to simplify into the form above merely means that the | |
636 | statement provides no equivalences to help simplify later | |
637 | statements. This does not prevent threading through E->dest. */ | |
4ee9c684 | 638 | for (bsi = bsi_start (e->dest); ! bsi_end_p (bsi); bsi_next (&bsi)) |
639 | { | |
a01d0a8b | 640 | tree cached_lhs; |
4ee9c684 | 641 | |
642 | stmt = bsi_stmt (bsi); | |
643 | ||
644 | /* Ignore empty statements and labels. */ | |
645 | if (IS_EMPTY_STMT (stmt) || TREE_CODE (stmt) == LABEL_EXPR) | |
646 | continue; | |
647 | ||
a01d0a8b | 648 | /* Safely handle threading across loop backedges. This is |
649 | over conservative, but still allows us to capture the | |
650 | majority of the cases where we can thread across a loop | |
651 | backedge. */ | |
652 | if ((e->flags & EDGE_DFS_BACK) != 0 | |
653 | && TREE_CODE (stmt) != COND_EXPR | |
654 | && TREE_CODE (stmt) != SWITCH_EXPR) | |
655 | return; | |
656 | ||
657 | /* If the statement has volatile operands, then we assume we | |
658 | can not thread through this block. This is overly | |
659 | conservative in some ways. */ | |
660 | if (TREE_CODE (stmt) == ASM_EXPR && ASM_VOLATILE_P (stmt)) | |
661 | return; | |
662 | ||
4ee9c684 | 663 | /* If this is not a MODIFY_EXPR which sets an SSA_NAME to a new |
a01d0a8b | 664 | value, then do not try to simplify this statement as it will |
665 | not simplify in any way that is helpful for jump threading. */ | |
4ee9c684 | 666 | if (TREE_CODE (stmt) != MODIFY_EXPR |
667 | || TREE_CODE (TREE_OPERAND (stmt, 0)) != SSA_NAME) | |
a01d0a8b | 668 | continue; |
4ee9c684 | 669 | |
670 | /* At this point we have a statement which assigns an RHS to an | |
a01d0a8b | 671 | SSA_VAR on the LHS. We want to try and simplify this statement |
672 | to expose more context sensitive equivalences which in turn may | |
673 | allow us to simplify the condition at the end of the loop. */ | |
4ee9c684 | 674 | if (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME) |
675 | cached_lhs = TREE_OPERAND (stmt, 1); | |
676 | else | |
4ee9c684 | 677 | { |
678 | /* Copy the operands. */ | |
b66731e8 | 679 | tree *copy; |
680 | ssa_op_iter iter; | |
681 | use_operand_p use_p; | |
682 | unsigned int num, i = 0; | |
4ee9c684 | 683 | |
b66731e8 | 684 | num = NUM_SSA_OPERANDS (stmt, (SSA_OP_USE | SSA_OP_VUSE)); |
685 | copy = xcalloc (num, sizeof (tree)); | |
4ee9c684 | 686 | |
b66731e8 | 687 | /* Make a copy of the uses & vuses into USES_COPY, then cprop into |
688 | the operands. */ | |
689 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE | SSA_OP_VUSE) | |
4ee9c684 | 690 | { |
691 | tree tmp = NULL; | |
b66731e8 | 692 | tree use = USE_FROM_PTR (use_p); |
4ee9c684 | 693 | |
b66731e8 | 694 | copy[i++] = use; |
695 | if (TREE_CODE (use) == SSA_NAME) | |
696 | tmp = SSA_NAME_VALUE (use); | |
4c7a0518 | 697 | if (tmp && TREE_CODE (tmp) != VALUE_HANDLE) |
b66731e8 | 698 | SET_USE (use_p, tmp); |
4ee9c684 | 699 | } |
700 | ||
a01d0a8b | 701 | /* Try to fold/lookup the new expression. Inserting the |
702 | expression into the hash table is unlikely to help | |
703 | simplify anything later, so just query the hashtable. */ | |
704 | cached_lhs = fold (TREE_OPERAND (stmt, 1)); | |
705 | if (TREE_CODE (cached_lhs) != SSA_NAME | |
706 | && !is_gimple_min_invariant (cached_lhs)) | |
707 | cached_lhs = lookup_avail_expr (stmt, false); | |
4ee9c684 | 708 | |
4ee9c684 | 709 | |
b66731e8 | 710 | /* Restore the statement's original uses/defs. */ |
711 | i = 0; | |
712 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE | SSA_OP_VUSE) | |
713 | SET_USE (use_p, copy[i++]); | |
4ee9c684 | 714 | |
b66731e8 | 715 | free (copy); |
4ee9c684 | 716 | } |
717 | ||
a01d0a8b | 718 | /* Record the context sensitive equivalence if we were able |
719 | to simplify this statement. */ | |
720 | if (cached_lhs | |
721 | && (TREE_CODE (cached_lhs) == SSA_NAME | |
722 | || is_gimple_min_invariant (cached_lhs))) | |
723 | record_const_or_copy (TREE_OPERAND (stmt, 0), cached_lhs); | |
4ee9c684 | 724 | } |
725 | ||
a01d0a8b | 726 | /* If we stopped at a COND_EXPR or SWITCH_EXPR, see if we know which arm |
727 | will be taken. */ | |
4ee9c684 | 728 | if (stmt |
729 | && (TREE_CODE (stmt) == COND_EXPR | |
a01d0a8b | 730 | || TREE_CODE (stmt) == GOTO_EXPR |
731 | || TREE_CODE (stmt) == SWITCH_EXPR)) | |
4ee9c684 | 732 | { |
733 | tree cond, cached_lhs; | |
4ee9c684 | 734 | |
735 | /* Now temporarily cprop the operands and try to find the resulting | |
736 | expression in the hash tables. */ | |
737 | if (TREE_CODE (stmt) == COND_EXPR) | |
738 | cond = COND_EXPR_COND (stmt); | |
6d7413d8 | 739 | else if (TREE_CODE (stmt) == GOTO_EXPR) |
740 | cond = GOTO_DESTINATION (stmt); | |
4ee9c684 | 741 | else |
742 | cond = SWITCH_COND (stmt); | |
743 | ||
ce45a448 | 744 | if (COMPARISON_CLASS_P (cond)) |
4ee9c684 | 745 | { |
746 | tree dummy_cond, op0, op1; | |
747 | enum tree_code cond_code; | |
748 | ||
749 | op0 = TREE_OPERAND (cond, 0); | |
750 | op1 = TREE_OPERAND (cond, 1); | |
751 | cond_code = TREE_CODE (cond); | |
752 | ||
753 | /* Get the current value of both operands. */ | |
754 | if (TREE_CODE (op0) == SSA_NAME) | |
755 | { | |
4c7a0518 | 756 | tree tmp = SSA_NAME_VALUE (op0); |
757 | if (tmp && TREE_CODE (tmp) != VALUE_HANDLE) | |
4ee9c684 | 758 | op0 = tmp; |
759 | } | |
760 | ||
761 | if (TREE_CODE (op1) == SSA_NAME) | |
762 | { | |
4c7a0518 | 763 | tree tmp = SSA_NAME_VALUE (op1); |
764 | if (tmp && TREE_CODE (tmp) != VALUE_HANDLE) | |
4ee9c684 | 765 | op1 = tmp; |
766 | } | |
767 | ||
768 | /* Stuff the operator and operands into our dummy conditional | |
769 | expression, creating the dummy conditional if necessary. */ | |
770 | dummy_cond = walk_data->global_data; | |
771 | if (! dummy_cond) | |
772 | { | |
773 | dummy_cond = build (cond_code, boolean_type_node, op0, op1); | |
774 | dummy_cond = build (COND_EXPR, void_type_node, | |
775 | dummy_cond, NULL, NULL); | |
776 | walk_data->global_data = dummy_cond; | |
777 | } | |
778 | else | |
779 | { | |
58f52dd4 | 780 | TREE_SET_CODE (COND_EXPR_COND (dummy_cond), cond_code); |
781 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op0; | |
782 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1) = op1; | |
4ee9c684 | 783 | } |
784 | ||
785 | /* If the conditional folds to an invariant, then we are done, | |
786 | otherwise look it up in the hash tables. */ | |
787 | cached_lhs = local_fold (COND_EXPR_COND (dummy_cond)); | |
788 | if (! is_gimple_min_invariant (cached_lhs)) | |
4ee9c684 | 789 | { |
8363860b | 790 | cached_lhs = lookup_avail_expr (dummy_cond, false); |
791 | if (!cached_lhs || ! is_gimple_min_invariant (cached_lhs)) | |
792 | cached_lhs = simplify_cond_and_lookup_avail_expr (dummy_cond, | |
793 | NULL, | |
794 | false); | |
4ee9c684 | 795 | } |
796 | } | |
797 | /* We can have conditionals which just test the state of a | |
798 | variable rather than use a relational operator. These are | |
799 | simpler to handle. */ | |
800 | else if (TREE_CODE (cond) == SSA_NAME) | |
801 | { | |
802 | cached_lhs = cond; | |
4c7a0518 | 803 | cached_lhs = SSA_NAME_VALUE (cached_lhs); |
4ee9c684 | 804 | if (cached_lhs && ! is_gimple_min_invariant (cached_lhs)) |
a01d0a8b | 805 | cached_lhs = NULL; |
4ee9c684 | 806 | } |
807 | else | |
9c629f0e | 808 | cached_lhs = lookup_avail_expr (stmt, false); |
4ee9c684 | 809 | |
810 | if (cached_lhs) | |
811 | { | |
812 | edge taken_edge = find_taken_edge (e->dest, cached_lhs); | |
813 | basic_block dest = (taken_edge ? taken_edge->dest : NULL); | |
814 | ||
6c3a778e | 815 | if (dest == e->dest) |
4ee9c684 | 816 | return; |
817 | ||
818 | /* If we have a known destination for the conditional, then | |
819 | we can perform this optimization, which saves at least one | |
820 | conditional jump each time it applies since we get to | |
dac49aa5 | 821 | bypass the conditional at our original destination. */ |
4ee9c684 | 822 | if (dest) |
823 | { | |
2f0993e7 | 824 | struct edge_info *edge_info; |
825 | ||
615dd397 | 826 | update_bb_profile_for_threading (e->dest, EDGE_FREQUENCY (e), |
827 | e->count, taken_edge); | |
2f0993e7 | 828 | if (e->aux) |
829 | edge_info = e->aux; | |
830 | else | |
831 | edge_info = allocate_edge_info (e); | |
832 | edge_info->redirection_target = taken_edge; | |
a8046f60 | 833 | bb_ann (e->dest)->incoming_edge_threaded = true; |
4ee9c684 | 834 | } |
835 | } | |
836 | } | |
837 | } | |
838 | ||
839 | ||
4ee9c684 | 840 | /* Initialize local stacks for this optimizer and record equivalences |
841 | upon entry to BB. Equivalences can come from the edge traversed to | |
842 | reach BB or they may come from PHI nodes at the start of BB. */ | |
843 | ||
844 | static void | |
2f0993e7 | 845 | dom_opt_initialize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
846 | basic_block bb) | |
4ee9c684 | 847 | { |
848 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
849 | fprintf (dump_file, "\n\nOptimizing block #%d\n\n", bb->index); | |
850 | ||
dd2d357d | 851 | /* Push a marker on the stacks of local information so that we know how |
852 | far to unwind when we finalize this block. */ | |
046bfc77 | 853 | VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE); |
046bfc77 | 854 | VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE); |
855 | VEC_safe_push (tree, heap, nonzero_vars_stack, NULL_TREE); | |
856 | VEC_safe_push (tree, heap, vrp_variables_stack, NULL_TREE); | |
9c629f0e | 857 | |
2f0993e7 | 858 | record_equivalences_from_incoming_edge (bb); |
4ee9c684 | 859 | |
860 | /* PHI nodes can create equivalences too. */ | |
2f0993e7 | 861 | record_equivalences_from_phis (bb); |
4ee9c684 | 862 | } |
863 | ||
864 | /* Given an expression EXPR (a relational expression or a statement), | |
865 | initialize the hash table element pointed by by ELEMENT. */ | |
866 | ||
867 | static void | |
868 | initialize_hash_element (tree expr, tree lhs, struct expr_hash_elt *element) | |
869 | { | |
870 | /* Hash table elements may be based on conditional expressions or statements. | |
871 | ||
872 | For the former case, we have no annotation and we want to hash the | |
873 | conditional expression. In the latter case we have an annotation and | |
874 | we want to record the expression the statement evaluates. */ | |
ce45a448 | 875 | if (COMPARISON_CLASS_P (expr) || TREE_CODE (expr) == TRUTH_NOT_EXPR) |
4ee9c684 | 876 | { |
b66731e8 | 877 | element->stmt = NULL; |
4ee9c684 | 878 | element->rhs = expr; |
879 | } | |
880 | else if (TREE_CODE (expr) == COND_EXPR) | |
881 | { | |
b66731e8 | 882 | element->stmt = expr; |
4ee9c684 | 883 | element->rhs = COND_EXPR_COND (expr); |
884 | } | |
885 | else if (TREE_CODE (expr) == SWITCH_EXPR) | |
886 | { | |
b66731e8 | 887 | element->stmt = expr; |
4ee9c684 | 888 | element->rhs = SWITCH_COND (expr); |
889 | } | |
890 | else if (TREE_CODE (expr) == RETURN_EXPR && TREE_OPERAND (expr, 0)) | |
891 | { | |
b66731e8 | 892 | element->stmt = expr; |
4ee9c684 | 893 | element->rhs = TREE_OPERAND (TREE_OPERAND (expr, 0), 1); |
894 | } | |
a01d0a8b | 895 | else if (TREE_CODE (expr) == GOTO_EXPR) |
896 | { | |
b66731e8 | 897 | element->stmt = expr; |
a01d0a8b | 898 | element->rhs = GOTO_DESTINATION (expr); |
899 | } | |
4ee9c684 | 900 | else |
901 | { | |
b66731e8 | 902 | element->stmt = expr; |
4ee9c684 | 903 | element->rhs = TREE_OPERAND (expr, 1); |
904 | } | |
905 | ||
906 | element->lhs = lhs; | |
907 | element->hash = avail_expr_hash (element); | |
908 | } | |
909 | ||
910 | /* Remove all the expressions in LOCALS from TABLE, stopping when there are | |
911 | LIMIT entries left in LOCALs. */ | |
912 | ||
913 | static void | |
9c629f0e | 914 | remove_local_expressions_from_table (void) |
4ee9c684 | 915 | { |
4ee9c684 | 916 | /* Remove all the expressions made available in this block. */ |
046bfc77 | 917 | while (VEC_length (tree, avail_exprs_stack) > 0) |
4ee9c684 | 918 | { |
919 | struct expr_hash_elt element; | |
046bfc77 | 920 | tree expr = VEC_pop (tree, avail_exprs_stack); |
9c629f0e | 921 | |
922 | if (expr == NULL_TREE) | |
923 | break; | |
4ee9c684 | 924 | |
925 | initialize_hash_element (expr, NULL, &element); | |
9c629f0e | 926 | htab_remove_elt_with_hash (avail_exprs, &element, element.hash); |
4ee9c684 | 927 | } |
928 | } | |
929 | ||
930 | /* Use the SSA_NAMES in LOCALS to restore TABLE to its original | |
365db11e | 931 | state, stopping when there are LIMIT entries left in LOCALs. */ |
4ee9c684 | 932 | |
933 | static void | |
f1a82013 | 934 | restore_nonzero_vars_to_original_value (void) |
4ee9c684 | 935 | { |
046bfc77 | 936 | while (VEC_length (tree, nonzero_vars_stack) > 0) |
4ee9c684 | 937 | { |
046bfc77 | 938 | tree name = VEC_pop (tree, nonzero_vars_stack); |
180d0339 | 939 | |
940 | if (name == NULL) | |
941 | break; | |
942 | ||
943 | bitmap_clear_bit (nonzero_vars, SSA_NAME_VERSION (name)); | |
4ee9c684 | 944 | } |
945 | } | |
946 | ||
da43203c | 947 | /* Use the source/dest pairs in CONST_AND_COPIES_STACK to restore |
948 | CONST_AND_COPIES to its original state, stopping when we hit a | |
949 | NULL marker. */ | |
4ee9c684 | 950 | |
951 | static void | |
da43203c | 952 | restore_vars_to_original_value (void) |
4ee9c684 | 953 | { |
046bfc77 | 954 | while (VEC_length (tree, const_and_copies_stack) > 0) |
4ee9c684 | 955 | { |
956 | tree prev_value, dest; | |
957 | ||
046bfc77 | 958 | dest = VEC_pop (tree, const_and_copies_stack); |
4ee9c684 | 959 | |
da43203c | 960 | if (dest == NULL) |
961 | break; | |
962 | ||
046bfc77 | 963 | prev_value = VEC_pop (tree, const_and_copies_stack); |
4c7a0518 | 964 | SSA_NAME_VALUE (dest) = prev_value; |
4ee9c684 | 965 | } |
966 | } | |
967 | ||
4ee9c684 | 968 | /* We have finished processing the dominator children of BB, perform |
969 | any finalization actions in preparation for leaving this node in | |
970 | the dominator tree. */ | |
971 | ||
972 | static void | |
973 | dom_opt_finalize_block (struct dom_walk_data *walk_data, basic_block bb) | |
974 | { | |
4ee9c684 | 975 | tree last; |
976 | ||
1fff48e8 | 977 | /* If we are at a leaf node in the dominator tree, see if we can thread |
4ee9c684 | 978 | the edge from BB through its successor. |
979 | ||
980 | Do this before we remove entries from our equivalence tables. */ | |
ea091dfd | 981 | if (single_succ_p (bb) |
982 | && (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0 | |
983 | && (get_immediate_dominator (CDI_DOMINATORS, single_succ (bb)) != bb | |
984 | || phi_nodes (single_succ (bb)))) | |
4ee9c684 | 985 | |
986 | { | |
ea091dfd | 987 | thread_across_edge (walk_data, single_succ_edge (bb)); |
4ee9c684 | 988 | } |
989 | else if ((last = last_stmt (bb)) | |
990 | && TREE_CODE (last) == COND_EXPR | |
ce45a448 | 991 | && (COMPARISON_CLASS_P (COND_EXPR_COND (last)) |
4ee9c684 | 992 | || TREE_CODE (COND_EXPR_COND (last)) == SSA_NAME) |
cd665a06 | 993 | && EDGE_COUNT (bb->succs) == 2 |
994 | && (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL) == 0 | |
995 | && (EDGE_SUCC (bb, 1)->flags & EDGE_ABNORMAL) == 0) | |
4ee9c684 | 996 | { |
997 | edge true_edge, false_edge; | |
4ee9c684 | 998 | |
999 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
1000 | ||
4ee9c684 | 1001 | /* If the THEN arm is the end of a dominator tree or has PHI nodes, |
1002 | then try to thread through its edge. */ | |
1003 | if (get_immediate_dominator (CDI_DOMINATORS, true_edge->dest) != bb | |
1004 | || phi_nodes (true_edge->dest)) | |
1005 | { | |
2f0993e7 | 1006 | struct edge_info *edge_info; |
1007 | unsigned int i; | |
1008 | ||
9c629f0e | 1009 | /* Push a marker onto the available expression stack so that we |
1010 | unwind any expressions related to the TRUE arm before processing | |
1011 | the false arm below. */ | |
046bfc77 | 1012 | VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE); |
046bfc77 | 1013 | VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE); |
9c629f0e | 1014 | |
2f0993e7 | 1015 | edge_info = true_edge->aux; |
1016 | ||
1017 | /* If we have info associated with this edge, record it into | |
1018 | our equivalency tables. */ | |
1019 | if (edge_info) | |
4ee9c684 | 1020 | { |
2f0993e7 | 1021 | tree *cond_equivalences = edge_info->cond_equivalences; |
1022 | tree lhs = edge_info->lhs; | |
1023 | tree rhs = edge_info->rhs; | |
1024 | ||
a01d0a8b | 1025 | /* If we have a simple NAME = VALUE equivalency record it. */ |
1026 | if (lhs && TREE_CODE (lhs) == SSA_NAME) | |
2f0993e7 | 1027 | record_const_or_copy (lhs, rhs); |
1028 | ||
1029 | /* If we have 0 = COND or 1 = COND equivalences, record them | |
1030 | into our expression hash tables. */ | |
1031 | if (cond_equivalences) | |
1032 | for (i = 0; i < edge_info->max_cond_equivalences; i += 2) | |
1033 | { | |
1034 | tree expr = cond_equivalences[i]; | |
1035 | tree value = cond_equivalences[i + 1]; | |
1036 | ||
1037 | record_cond (expr, value); | |
1038 | } | |
4ee9c684 | 1039 | } |
4ee9c684 | 1040 | |
1041 | /* Now thread the edge. */ | |
1042 | thread_across_edge (walk_data, true_edge); | |
1043 | ||
1044 | /* And restore the various tables to their state before | |
1045 | we threaded this edge. */ | |
9c629f0e | 1046 | remove_local_expressions_from_table (); |
da43203c | 1047 | restore_vars_to_original_value (); |
4ee9c684 | 1048 | } |
1049 | ||
1050 | /* Similarly for the ELSE arm. */ | |
1051 | if (get_immediate_dominator (CDI_DOMINATORS, false_edge->dest) != bb | |
1052 | || phi_nodes (false_edge->dest)) | |
1053 | { | |
2f0993e7 | 1054 | struct edge_info *edge_info; |
1055 | unsigned int i; | |
1056 | ||
1057 | edge_info = false_edge->aux; | |
1058 | ||
1059 | /* If we have info associated with this edge, record it into | |
1060 | our equivalency tables. */ | |
1061 | if (edge_info) | |
4ee9c684 | 1062 | { |
2f0993e7 | 1063 | tree *cond_equivalences = edge_info->cond_equivalences; |
1064 | tree lhs = edge_info->lhs; | |
1065 | tree rhs = edge_info->rhs; | |
1066 | ||
a01d0a8b | 1067 | /* If we have a simple NAME = VALUE equivalency record it. */ |
1068 | if (lhs && TREE_CODE (lhs) == SSA_NAME) | |
2f0993e7 | 1069 | record_const_or_copy (lhs, rhs); |
1070 | ||
1071 | /* If we have 0 = COND or 1 = COND equivalences, record them | |
1072 | into our expression hash tables. */ | |
1073 | if (cond_equivalences) | |
1074 | for (i = 0; i < edge_info->max_cond_equivalences; i += 2) | |
1075 | { | |
1076 | tree expr = cond_equivalences[i]; | |
1077 | tree value = cond_equivalences[i + 1]; | |
1078 | ||
1079 | record_cond (expr, value); | |
1080 | } | |
4ee9c684 | 1081 | } |
4ee9c684 | 1082 | |
1083 | thread_across_edge (walk_data, false_edge); | |
1084 | ||
1085 | /* No need to remove local expressions from our tables | |
1086 | or restore vars to their original value as that will | |
1087 | be done immediately below. */ | |
1088 | } | |
1089 | } | |
1090 | ||
9c629f0e | 1091 | remove_local_expressions_from_table (); |
180d0339 | 1092 | restore_nonzero_vars_to_original_value (); |
da43203c | 1093 | restore_vars_to_original_value (); |
4ee9c684 | 1094 | |
1095 | /* Remove VRP records associated with this basic block. They are no | |
1096 | longer valid. | |
1097 | ||
1098 | To be efficient, we note which variables have had their values | |
1099 | constrained in this block. So walk over each variable in the | |
1100 | VRP_VARIABLEs array. */ | |
046bfc77 | 1101 | while (VEC_length (tree, vrp_variables_stack) > 0) |
4ee9c684 | 1102 | { |
046bfc77 | 1103 | tree var = VEC_pop (tree, vrp_variables_stack); |
de29fdfe | 1104 | struct vrp_hash_elt vrp_hash_elt, *vrp_hash_elt_p; |
d0d897b6 | 1105 | void **slot; |
4ee9c684 | 1106 | |
1107 | /* Each variable has a stack of value range records. We want to | |
1108 | invalidate those associated with our basic block. So we walk | |
1109 | the array backwards popping off records associated with our | |
1110 | block. Once we hit a record not associated with our block | |
1111 | we are done. */ | |
180d0339 | 1112 | varray_type var_vrp_records; |
1113 | ||
180d0339 | 1114 | if (var == NULL) |
1115 | break; | |
4ee9c684 | 1116 | |
d0d897b6 | 1117 | vrp_hash_elt.var = var; |
1118 | vrp_hash_elt.records = NULL; | |
1119 | ||
1120 | slot = htab_find_slot (vrp_data, &vrp_hash_elt, NO_INSERT); | |
1121 | ||
de29fdfe | 1122 | vrp_hash_elt_p = (struct vrp_hash_elt *) *slot; |
1123 | var_vrp_records = vrp_hash_elt_p->records; | |
1124 | ||
4ee9c684 | 1125 | while (VARRAY_ACTIVE_SIZE (var_vrp_records) > 0) |
1126 | { | |
1127 | struct vrp_element *element | |
1128 | = (struct vrp_element *)VARRAY_TOP_GENERIC_PTR (var_vrp_records); | |
1129 | ||
1130 | if (element->bb != bb) | |
1131 | break; | |
1132 | ||
1133 | VARRAY_POP (var_vrp_records); | |
1134 | } | |
4ee9c684 | 1135 | } |
1136 | ||
a721131d | 1137 | /* If we queued any statements to rescan in this block, then |
1138 | go ahead and rescan them now. */ | |
046bfc77 | 1139 | while (VEC_length (tree, stmts_to_rescan) > 0) |
4ee9c684 | 1140 | { |
046bfc77 | 1141 | tree stmt = VEC_last (tree, stmts_to_rescan); |
a721131d | 1142 | basic_block stmt_bb = bb_for_stmt (stmt); |
1143 | ||
1144 | if (stmt_bb != bb) | |
1145 | break; | |
1146 | ||
046bfc77 | 1147 | VEC_pop (tree, stmts_to_rescan); |
88dbf20f | 1148 | mark_new_vars_to_rename (stmt); |
4ee9c684 | 1149 | } |
1150 | } | |
1151 | ||
1152 | /* PHI nodes can create equivalences too. | |
1153 | ||
1154 | Ignoring any alternatives which are the same as the result, if | |
1155 | all the alternatives are equal, then the PHI node creates an | |
6e9a4371 | 1156 | equivalence. |
1157 | ||
1158 | Additionally, if all the PHI alternatives are known to have a nonzero | |
1159 | value, then the result of this PHI is known to have a nonzero value, | |
1160 | even if we do not know its exact value. */ | |
1161 | ||
4ee9c684 | 1162 | static void |
2f0993e7 | 1163 | record_equivalences_from_phis (basic_block bb) |
4ee9c684 | 1164 | { |
4ee9c684 | 1165 | tree phi; |
1166 | ||
04f8eea3 | 1167 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
4ee9c684 | 1168 | { |
1169 | tree lhs = PHI_RESULT (phi); | |
1170 | tree rhs = NULL; | |
1171 | int i; | |
1172 | ||
1173 | for (i = 0; i < PHI_NUM_ARGS (phi); i++) | |
1174 | { | |
1175 | tree t = PHI_ARG_DEF (phi, i); | |
1176 | ||
2fb4af30 | 1177 | /* Ignore alternatives which are the same as our LHS. Since |
1178 | LHS is a PHI_RESULT, it is known to be a SSA_NAME, so we | |
1179 | can simply compare pointers. */ | |
fcf57fc2 | 1180 | if (lhs == t) |
92527855 | 1181 | continue; |
1182 | ||
1183 | /* If we have not processed an alternative yet, then set | |
1184 | RHS to this alternative. */ | |
1185 | if (rhs == NULL) | |
1186 | rhs = t; | |
1187 | /* If we have processed an alternative (stored in RHS), then | |
1188 | see if it is equal to this one. If it isn't, then stop | |
1189 | the search. */ | |
1190 | else if (! operand_equal_for_phi_arg_p (rhs, t)) | |
4ee9c684 | 1191 | break; |
1192 | } | |
1193 | ||
1194 | /* If we had no interesting alternatives, then all the RHS alternatives | |
1195 | must have been the same as LHS. */ | |
1196 | if (!rhs) | |
1197 | rhs = lhs; | |
1198 | ||
1199 | /* If we managed to iterate through each PHI alternative without | |
1200 | breaking out of the loop, then we have a PHI which may create | |
1201 | a useful equivalence. We do not need to record unwind data for | |
1202 | this, since this is a true assignment and not an equivalence | |
365db11e | 1203 | inferred from a comparison. All uses of this ssa name are dominated |
4ee9c684 | 1204 | by this assignment, so unwinding just costs time and space. */ |
1205 | if (i == PHI_NUM_ARGS (phi) | |
1206 | && may_propagate_copy (lhs, rhs)) | |
4c7a0518 | 1207 | SSA_NAME_VALUE (lhs) = rhs; |
4ee9c684 | 1208 | |
6e9a4371 | 1209 | /* Now see if we know anything about the nonzero property for the |
1210 | result of this PHI. */ | |
1211 | for (i = 0; i < PHI_NUM_ARGS (phi); i++) | |
1212 | { | |
1213 | if (!PHI_ARG_NONZERO (phi, i)) | |
1214 | break; | |
1215 | } | |
1216 | ||
1217 | if (i == PHI_NUM_ARGS (phi)) | |
1218 | bitmap_set_bit (nonzero_vars, SSA_NAME_VERSION (PHI_RESULT (phi))); | |
4ee9c684 | 1219 | } |
1220 | } | |
1221 | ||
c0735efa | 1222 | /* Ignoring loop backedges, if BB has precisely one incoming edge then |
1223 | return that edge. Otherwise return NULL. */ | |
1224 | static edge | |
1225 | single_incoming_edge_ignoring_loop_edges (basic_block bb) | |
1226 | { | |
1227 | edge retval = NULL; | |
1228 | edge e; | |
cd665a06 | 1229 | edge_iterator ei; |
c0735efa | 1230 | |
cd665a06 | 1231 | FOR_EACH_EDGE (e, ei, bb->preds) |
c0735efa | 1232 | { |
1233 | /* A loop back edge can be identified by the destination of | |
1234 | the edge dominating the source of the edge. */ | |
1235 | if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest)) | |
1236 | continue; | |
1237 | ||
1238 | /* If we have already seen a non-loop edge, then we must have | |
1239 | multiple incoming non-loop edges and thus we return NULL. */ | |
1240 | if (retval) | |
1241 | return NULL; | |
1242 | ||
1243 | /* This is the first non-loop incoming edge we have found. Record | |
1244 | it. */ | |
1245 | retval = e; | |
1246 | } | |
1247 | ||
1248 | return retval; | |
1249 | } | |
1250 | ||
4ee9c684 | 1251 | /* Record any equivalences created by the incoming edge to BB. If BB |
1252 | has more than one incoming edge, then no equivalence is created. */ | |
1253 | ||
1254 | static void | |
2f0993e7 | 1255 | record_equivalences_from_incoming_edge (basic_block bb) |
4ee9c684 | 1256 | { |
2f0993e7 | 1257 | edge e; |
4ee9c684 | 1258 | basic_block parent; |
2f0993e7 | 1259 | struct edge_info *edge_info; |
4ee9c684 | 1260 | |
0975351b | 1261 | /* If our parent block ended with a control statement, then we may be |
4ee9c684 | 1262 | able to record some equivalences based on which outgoing edge from |
1263 | the parent was followed. */ | |
1264 | parent = get_immediate_dominator (CDI_DOMINATORS, bb); | |
4ee9c684 | 1265 | |
2f0993e7 | 1266 | e = single_incoming_edge_ignoring_loop_edges (bb); |
4ee9c684 | 1267 | |
2f0993e7 | 1268 | /* If we had a single incoming edge from our parent block, then enter |
1269 | any data associated with the edge into our tables. */ | |
1270 | if (e && e->src == parent) | |
4ee9c684 | 1271 | { |
2f0993e7 | 1272 | unsigned int i; |
4ee9c684 | 1273 | |
2f0993e7 | 1274 | edge_info = e->aux; |
4ee9c684 | 1275 | |
2f0993e7 | 1276 | if (edge_info) |
4ee9c684 | 1277 | { |
2f0993e7 | 1278 | tree lhs = edge_info->lhs; |
1279 | tree rhs = edge_info->rhs; | |
1280 | tree *cond_equivalences = edge_info->cond_equivalences; | |
1281 | ||
1282 | if (lhs) | |
1283 | record_equality (lhs, rhs); | |
1284 | ||
1285 | if (cond_equivalences) | |
4ee9c684 | 1286 | { |
2f0993e7 | 1287 | bool recorded_range = false; |
1288 | for (i = 0; i < edge_info->max_cond_equivalences; i += 2) | |
4ee9c684 | 1289 | { |
2f0993e7 | 1290 | tree expr = cond_equivalences[i]; |
1291 | tree value = cond_equivalences[i + 1]; | |
1292 | ||
1293 | record_cond (expr, value); | |
1294 | ||
1295 | /* For the first true equivalence, record range | |
1296 | information. We only do this for the first | |
1297 | true equivalence as it should dominate any | |
1298 | later true equivalences. */ | |
1299 | if (! recorded_range | |
1300 | && COMPARISON_CLASS_P (expr) | |
1301 | && value == boolean_true_node | |
1302 | && TREE_CONSTANT (TREE_OPERAND (expr, 1))) | |
1303 | { | |
1304 | record_range (expr, bb); | |
1305 | recorded_range = true; | |
1306 | } | |
4ee9c684 | 1307 | } |
1308 | } | |
4ee9c684 | 1309 | } |
1310 | } | |
4ee9c684 | 1311 | } |
1312 | ||
1313 | /* Dump SSA statistics on FILE. */ | |
1314 | ||
1315 | void | |
1316 | dump_dominator_optimization_stats (FILE *file) | |
1317 | { | |
1318 | long n_exprs; | |
1319 | ||
1320 | fprintf (file, "Total number of statements: %6ld\n\n", | |
1321 | opt_stats.num_stmts); | |
1322 | fprintf (file, "Exprs considered for dominator optimizations: %6ld\n", | |
1323 | opt_stats.num_exprs_considered); | |
1324 | ||
1325 | n_exprs = opt_stats.num_exprs_considered; | |
1326 | if (n_exprs == 0) | |
1327 | n_exprs = 1; | |
1328 | ||
1329 | fprintf (file, " Redundant expressions eliminated: %6ld (%.0f%%)\n", | |
1330 | opt_stats.num_re, PERCENT (opt_stats.num_re, | |
1331 | n_exprs)); | |
88dbf20f | 1332 | fprintf (file, " Constants propagated: %6ld\n", |
1333 | opt_stats.num_const_prop); | |
1334 | fprintf (file, " Copies propagated: %6ld\n", | |
1335 | opt_stats.num_copy_prop); | |
4ee9c684 | 1336 | |
1337 | fprintf (file, "\nHash table statistics:\n"); | |
1338 | ||
1339 | fprintf (file, " avail_exprs: "); | |
1340 | htab_statistics (file, avail_exprs); | |
1341 | } | |
1342 | ||
1343 | ||
1344 | /* Dump SSA statistics on stderr. */ | |
1345 | ||
1346 | void | |
1347 | debug_dominator_optimization_stats (void) | |
1348 | { | |
1349 | dump_dominator_optimization_stats (stderr); | |
1350 | } | |
1351 | ||
1352 | ||
1353 | /* Dump statistics for the hash table HTAB. */ | |
1354 | ||
1355 | static void | |
1356 | htab_statistics (FILE *file, htab_t htab) | |
1357 | { | |
1358 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
1359 | (long) htab_size (htab), | |
1360 | (long) htab_elements (htab), | |
1361 | htab_collisions (htab)); | |
1362 | } | |
1363 | ||
1364 | /* Record the fact that VAR has a nonzero value, though we may not know | |
1365 | its exact value. Note that if VAR is already known to have a nonzero | |
1366 | value, then we do nothing. */ | |
1367 | ||
1368 | static void | |
180d0339 | 1369 | record_var_is_nonzero (tree var) |
4ee9c684 | 1370 | { |
1371 | int indx = SSA_NAME_VERSION (var); | |
1372 | ||
1373 | if (bitmap_bit_p (nonzero_vars, indx)) | |
1374 | return; | |
1375 | ||
1376 | /* Mark it in the global table. */ | |
1377 | bitmap_set_bit (nonzero_vars, indx); | |
1378 | ||
1379 | /* Record this SSA_NAME so that we can reset the global table | |
1380 | when we leave this block. */ | |
046bfc77 | 1381 | VEC_safe_push (tree, heap, nonzero_vars_stack, var); |
4ee9c684 | 1382 | } |
1383 | ||
1384 | /* Enter a statement into the true/false expression hash table indicating | |
1385 | that the condition COND has the value VALUE. */ | |
1386 | ||
1387 | static void | |
9c629f0e | 1388 | record_cond (tree cond, tree value) |
4ee9c684 | 1389 | { |
1390 | struct expr_hash_elt *element = xmalloc (sizeof (struct expr_hash_elt)); | |
1391 | void **slot; | |
1392 | ||
1393 | initialize_hash_element (cond, value, element); | |
1394 | ||
1395 | slot = htab_find_slot_with_hash (avail_exprs, (void *)element, | |
67c4f309 | 1396 | element->hash, INSERT); |
4ee9c684 | 1397 | if (*slot == NULL) |
1398 | { | |
1399 | *slot = (void *) element; | |
046bfc77 | 1400 | VEC_safe_push (tree, heap, avail_exprs_stack, cond); |
4ee9c684 | 1401 | } |
1402 | else | |
1403 | free (element); | |
1404 | } | |
1405 | ||
2f0993e7 | 1406 | /* Build a new conditional using NEW_CODE, OP0 and OP1 and store |
1407 | the new conditional into *p, then store a boolean_true_node | |
822e391f | 1408 | into *(p + 1). */ |
2f0993e7 | 1409 | |
1410 | static void | |
1411 | build_and_record_new_cond (enum tree_code new_code, tree op0, tree op1, tree *p) | |
1412 | { | |
1413 | *p = build2 (new_code, boolean_type_node, op0, op1); | |
1414 | p++; | |
1415 | *p = boolean_true_node; | |
1416 | } | |
1417 | ||
1418 | /* Record that COND is true and INVERTED is false into the edge information | |
1419 | structure. Also record that any conditions dominated by COND are true | |
1420 | as well. | |
043d0665 | 1421 | |
1422 | For example, if a < b is true, then a <= b must also be true. */ | |
1423 | ||
1424 | static void | |
2f0993e7 | 1425 | record_conditions (struct edge_info *edge_info, tree cond, tree inverted) |
043d0665 | 1426 | { |
2f0993e7 | 1427 | tree op0, op1; |
1428 | ||
1429 | if (!COMPARISON_CLASS_P (cond)) | |
1430 | return; | |
1431 | ||
1432 | op0 = TREE_OPERAND (cond, 0); | |
1433 | op1 = TREE_OPERAND (cond, 1); | |
1434 | ||
043d0665 | 1435 | switch (TREE_CODE (cond)) |
1436 | { | |
1437 | case LT_EXPR: | |
043d0665 | 1438 | case GT_EXPR: |
2f0993e7 | 1439 | edge_info->max_cond_equivalences = 12; |
1440 | edge_info->cond_equivalences = xmalloc (12 * sizeof (tree)); | |
1441 | build_and_record_new_cond ((TREE_CODE (cond) == LT_EXPR | |
1442 | ? LE_EXPR : GE_EXPR), | |
1443 | op0, op1, &edge_info->cond_equivalences[4]); | |
1444 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, | |
1445 | &edge_info->cond_equivalences[6]); | |
1446 | build_and_record_new_cond (NE_EXPR, op0, op1, | |
1447 | &edge_info->cond_equivalences[8]); | |
1448 | build_and_record_new_cond (LTGT_EXPR, op0, op1, | |
1449 | &edge_info->cond_equivalences[10]); | |
043d0665 | 1450 | break; |
1451 | ||
1452 | case GE_EXPR: | |
1453 | case LE_EXPR: | |
2f0993e7 | 1454 | edge_info->max_cond_equivalences = 6; |
1455 | edge_info->cond_equivalences = xmalloc (6 * sizeof (tree)); | |
1456 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, | |
1457 | &edge_info->cond_equivalences[4]); | |
043d0665 | 1458 | break; |
1459 | ||
1460 | case EQ_EXPR: | |
2f0993e7 | 1461 | edge_info->max_cond_equivalences = 10; |
1462 | edge_info->cond_equivalences = xmalloc (10 * sizeof (tree)); | |
1463 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, | |
1464 | &edge_info->cond_equivalences[4]); | |
1465 | build_and_record_new_cond (LE_EXPR, op0, op1, | |
1466 | &edge_info->cond_equivalences[6]); | |
1467 | build_and_record_new_cond (GE_EXPR, op0, op1, | |
1468 | &edge_info->cond_equivalences[8]); | |
043d0665 | 1469 | break; |
1470 | ||
1471 | case UNORDERED_EXPR: | |
2f0993e7 | 1472 | edge_info->max_cond_equivalences = 16; |
1473 | edge_info->cond_equivalences = xmalloc (16 * sizeof (tree)); | |
1474 | build_and_record_new_cond (NE_EXPR, op0, op1, | |
1475 | &edge_info->cond_equivalences[4]); | |
1476 | build_and_record_new_cond (UNLE_EXPR, op0, op1, | |
1477 | &edge_info->cond_equivalences[6]); | |
1478 | build_and_record_new_cond (UNGE_EXPR, op0, op1, | |
1479 | &edge_info->cond_equivalences[8]); | |
1480 | build_and_record_new_cond (UNEQ_EXPR, op0, op1, | |
1481 | &edge_info->cond_equivalences[10]); | |
1482 | build_and_record_new_cond (UNLT_EXPR, op0, op1, | |
1483 | &edge_info->cond_equivalences[12]); | |
1484 | build_and_record_new_cond (UNGT_EXPR, op0, op1, | |
1485 | &edge_info->cond_equivalences[14]); | |
043d0665 | 1486 | break; |
1487 | ||
1488 | case UNLT_EXPR: | |
043d0665 | 1489 | case UNGT_EXPR: |
2f0993e7 | 1490 | edge_info->max_cond_equivalences = 8; |
1491 | edge_info->cond_equivalences = xmalloc (8 * sizeof (tree)); | |
1492 | build_and_record_new_cond ((TREE_CODE (cond) == UNLT_EXPR | |
1493 | ? UNLE_EXPR : UNGE_EXPR), | |
1494 | op0, op1, &edge_info->cond_equivalences[4]); | |
1495 | build_and_record_new_cond (NE_EXPR, op0, op1, | |
1496 | &edge_info->cond_equivalences[6]); | |
043d0665 | 1497 | break; |
1498 | ||
1499 | case UNEQ_EXPR: | |
2f0993e7 | 1500 | edge_info->max_cond_equivalences = 8; |
1501 | edge_info->cond_equivalences = xmalloc (8 * sizeof (tree)); | |
1502 | build_and_record_new_cond (UNLE_EXPR, op0, op1, | |
1503 | &edge_info->cond_equivalences[4]); | |
1504 | build_and_record_new_cond (UNGE_EXPR, op0, op1, | |
1505 | &edge_info->cond_equivalences[6]); | |
043d0665 | 1506 | break; |
1507 | ||
1508 | case LTGT_EXPR: | |
2f0993e7 | 1509 | edge_info->max_cond_equivalences = 8; |
1510 | edge_info->cond_equivalences = xmalloc (8 * sizeof (tree)); | |
1511 | build_and_record_new_cond (NE_EXPR, op0, op1, | |
1512 | &edge_info->cond_equivalences[4]); | |
1513 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, | |
1514 | &edge_info->cond_equivalences[6]); | |
1515 | break; | |
043d0665 | 1516 | |
1517 | default: | |
2f0993e7 | 1518 | edge_info->max_cond_equivalences = 4; |
1519 | edge_info->cond_equivalences = xmalloc (4 * sizeof (tree)); | |
043d0665 | 1520 | break; |
1521 | } | |
2f0993e7 | 1522 | |
1523 | /* Now store the original true and false conditions into the first | |
1524 | two slots. */ | |
1525 | edge_info->cond_equivalences[0] = cond; | |
1526 | edge_info->cond_equivalences[1] = boolean_true_node; | |
1527 | edge_info->cond_equivalences[2] = inverted; | |
1528 | edge_info->cond_equivalences[3] = boolean_false_node; | |
043d0665 | 1529 | } |
1530 | ||
4ee9c684 | 1531 | /* A helper function for record_const_or_copy and record_equality. |
1532 | Do the work of recording the value and undo info. */ | |
1533 | ||
1534 | static void | |
da43203c | 1535 | record_const_or_copy_1 (tree x, tree y, tree prev_x) |
4ee9c684 | 1536 | { |
4c7a0518 | 1537 | SSA_NAME_VALUE (x) = y; |
4ee9c684 | 1538 | |
046bfc77 | 1539 | VEC_reserve (tree, heap, const_and_copies_stack, 2); |
1540 | VEC_quick_push (tree, const_and_copies_stack, prev_x); | |
1541 | VEC_quick_push (tree, const_and_copies_stack, x); | |
4ee9c684 | 1542 | } |
1543 | ||
ba4c299c | 1544 | |
1545 | /* Return the loop depth of the basic block of the defining statement of X. | |
1546 | This number should not be treated as absolutely correct because the loop | |
1547 | information may not be completely up-to-date when dom runs. However, it | |
1548 | will be relatively correct, and as more passes are taught to keep loop info | |
1549 | up to date, the result will become more and more accurate. */ | |
1550 | ||
88dbf20f | 1551 | int |
ba4c299c | 1552 | loop_depth_of_name (tree x) |
1553 | { | |
1554 | tree defstmt; | |
1555 | basic_block defbb; | |
1556 | ||
1557 | /* If it's not an SSA_NAME, we have no clue where the definition is. */ | |
1558 | if (TREE_CODE (x) != SSA_NAME) | |
1559 | return 0; | |
1560 | ||
1561 | /* Otherwise return the loop depth of the defining statement's bb. | |
1562 | Note that there may not actually be a bb for this statement, if the | |
1563 | ssa_name is live on entry. */ | |
1564 | defstmt = SSA_NAME_DEF_STMT (x); | |
1565 | defbb = bb_for_stmt (defstmt); | |
1566 | if (!defbb) | |
1567 | return 0; | |
1568 | ||
1569 | return defbb->loop_depth; | |
1570 | } | |
1571 | ||
1572 | ||
4ee9c684 | 1573 | /* Record that X is equal to Y in const_and_copies. Record undo |
f0458177 | 1574 | information in the block-local vector. */ |
4ee9c684 | 1575 | |
1576 | static void | |
da43203c | 1577 | record_const_or_copy (tree x, tree y) |
4ee9c684 | 1578 | { |
4c7a0518 | 1579 | tree prev_x = SSA_NAME_VALUE (x); |
4ee9c684 | 1580 | |
1581 | if (TREE_CODE (y) == SSA_NAME) | |
1582 | { | |
4c7a0518 | 1583 | tree tmp = SSA_NAME_VALUE (y); |
4ee9c684 | 1584 | if (tmp) |
1585 | y = tmp; | |
1586 | } | |
1587 | ||
da43203c | 1588 | record_const_or_copy_1 (x, y, prev_x); |
4ee9c684 | 1589 | } |
1590 | ||
1591 | /* Similarly, but assume that X and Y are the two operands of an EQ_EXPR. | |
1592 | This constrains the cases in which we may treat this as assignment. */ | |
1593 | ||
1594 | static void | |
da43203c | 1595 | record_equality (tree x, tree y) |
4ee9c684 | 1596 | { |
1597 | tree prev_x = NULL, prev_y = NULL; | |
1598 | ||
1599 | if (TREE_CODE (x) == SSA_NAME) | |
4c7a0518 | 1600 | prev_x = SSA_NAME_VALUE (x); |
4ee9c684 | 1601 | if (TREE_CODE (y) == SSA_NAME) |
4c7a0518 | 1602 | prev_y = SSA_NAME_VALUE (y); |
4ee9c684 | 1603 | |
ba4c299c | 1604 | /* If one of the previous values is invariant, or invariant in more loops |
1605 | (by depth), then use that. | |
4ee9c684 | 1606 | Otherwise it doesn't matter which value we choose, just so |
1607 | long as we canonicalize on one value. */ | |
1608 | if (TREE_INVARIANT (y)) | |
1609 | ; | |
ba4c299c | 1610 | else if (TREE_INVARIANT (x) || (loop_depth_of_name (x) <= loop_depth_of_name (y))) |
4ee9c684 | 1611 | prev_x = x, x = y, y = prev_x, prev_x = prev_y; |
1612 | else if (prev_x && TREE_INVARIANT (prev_x)) | |
1613 | x = y, y = prev_x, prev_x = prev_y; | |
4c7a0518 | 1614 | else if (prev_y && TREE_CODE (prev_y) != VALUE_HANDLE) |
4ee9c684 | 1615 | y = prev_y; |
1616 | ||
1617 | /* After the swapping, we must have one SSA_NAME. */ | |
1618 | if (TREE_CODE (x) != SSA_NAME) | |
1619 | return; | |
1620 | ||
1621 | /* For IEEE, -0.0 == 0.0, so we don't necessarily know the sign of a | |
1622 | variable compared against zero. If we're honoring signed zeros, | |
1623 | then we cannot record this value unless we know that the value is | |
365db11e | 1624 | nonzero. */ |
4ee9c684 | 1625 | if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (x))) |
1626 | && (TREE_CODE (y) != REAL_CST | |
1627 | || REAL_VALUES_EQUAL (dconst0, TREE_REAL_CST (y)))) | |
1628 | return; | |
1629 | ||
da43203c | 1630 | record_const_or_copy_1 (x, y, prev_x); |
4ee9c684 | 1631 | } |
1632 | ||
78f29aa3 | 1633 | /* Return true, if it is ok to do folding of an associative expression. |
1634 | EXP is the tree for the associative expression. */ | |
1635 | ||
1636 | static inline bool | |
1637 | unsafe_associative_fp_binop (tree exp) | |
1638 | { | |
1639 | enum tree_code code = TREE_CODE (exp); | |
1640 | return !(!flag_unsafe_math_optimizations | |
1e483325 | 1641 | && (code == MULT_EXPR || code == PLUS_EXPR |
1642 | || code == MINUS_EXPR) | |
78f29aa3 | 1643 | && FLOAT_TYPE_P (TREE_TYPE (exp))); |
1644 | } | |
1645 | ||
119a0489 | 1646 | /* Returns true when STMT is a simple iv increment. It detects the |
1647 | following situation: | |
1648 | ||
1649 | i_1 = phi (..., i_2) | |
1650 | i_2 = i_1 +/- ... */ | |
1651 | ||
1652 | static bool | |
1653 | simple_iv_increment_p (tree stmt) | |
1654 | { | |
1655 | tree lhs, rhs, preinc, phi; | |
1656 | unsigned i; | |
1657 | ||
1658 | if (TREE_CODE (stmt) != MODIFY_EXPR) | |
1659 | return false; | |
1660 | ||
1661 | lhs = TREE_OPERAND (stmt, 0); | |
1662 | if (TREE_CODE (lhs) != SSA_NAME) | |
1663 | return false; | |
1664 | ||
1665 | rhs = TREE_OPERAND (stmt, 1); | |
1666 | ||
1667 | if (TREE_CODE (rhs) != PLUS_EXPR | |
1668 | && TREE_CODE (rhs) != MINUS_EXPR) | |
1669 | return false; | |
1670 | ||
1671 | preinc = TREE_OPERAND (rhs, 0); | |
1672 | if (TREE_CODE (preinc) != SSA_NAME) | |
1673 | return false; | |
1674 | ||
1675 | phi = SSA_NAME_DEF_STMT (preinc); | |
1676 | if (TREE_CODE (phi) != PHI_NODE) | |
1677 | return false; | |
1678 | ||
1679 | for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++) | |
1680 | if (PHI_ARG_DEF (phi, i) == lhs) | |
1681 | return true; | |
1682 | ||
1683 | return false; | |
1684 | } | |
1685 | ||
4ee9c684 | 1686 | /* STMT is a MODIFY_EXPR for which we were unable to find RHS in the |
1687 | hash tables. Try to simplify the RHS using whatever equivalences | |
1688 | we may have recorded. | |
1689 | ||
1690 | If we are able to simplify the RHS, then lookup the simplified form in | |
1691 | the hash table and return the result. Otherwise return NULL. */ | |
1692 | ||
1693 | static tree | |
1694 | simplify_rhs_and_lookup_avail_expr (struct dom_walk_data *walk_data, | |
ac4bd4cc | 1695 | tree stmt, int insert) |
4ee9c684 | 1696 | { |
1697 | tree rhs = TREE_OPERAND (stmt, 1); | |
1698 | enum tree_code rhs_code = TREE_CODE (rhs); | |
1699 | tree result = NULL; | |
4ee9c684 | 1700 | |
1701 | /* If we have lhs = ~x, look and see if we earlier had x = ~y. | |
1702 | In which case we can change this statement to be lhs = y. | |
1703 | Which can then be copy propagated. | |
1704 | ||
1705 | Similarly for negation. */ | |
1706 | if ((rhs_code == BIT_NOT_EXPR || rhs_code == NEGATE_EXPR) | |
1707 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) | |
1708 | { | |
1709 | /* Get the definition statement for our RHS. */ | |
1710 | tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0)); | |
1711 | ||
1712 | /* See if the RHS_DEF_STMT has the same form as our statement. */ | |
1713 | if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR | |
1714 | && TREE_CODE (TREE_OPERAND (rhs_def_stmt, 1)) == rhs_code) | |
1715 | { | |
1716 | tree rhs_def_operand; | |
1717 | ||
1718 | rhs_def_operand = TREE_OPERAND (TREE_OPERAND (rhs_def_stmt, 1), 0); | |
1719 | ||
1720 | /* Verify that RHS_DEF_OPERAND is a suitable SSA variable. */ | |
1721 | if (TREE_CODE (rhs_def_operand) == SSA_NAME | |
1722 | && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand)) | |
1723 | result = update_rhs_and_lookup_avail_expr (stmt, | |
1724 | rhs_def_operand, | |
4ee9c684 | 1725 | insert); |
1726 | } | |
1727 | } | |
1728 | ||
1729 | /* If we have z = (x OP C1), see if we earlier had x = y OP C2. | |
1730 | If OP is associative, create and fold (y OP C2) OP C1 which | |
1731 | should result in (y OP C3), use that as the RHS for the | |
1732 | assignment. Add minus to this, as we handle it specially below. */ | |
1733 | if ((associative_tree_code (rhs_code) || rhs_code == MINUS_EXPR) | |
1734 | && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME | |
1735 | && is_gimple_min_invariant (TREE_OPERAND (rhs, 1))) | |
1736 | { | |
1737 | tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0)); | |
1738 | ||
119a0489 | 1739 | /* If the statement defines an induction variable, do not propagate |
1740 | its value, so that we do not create overlapping life ranges. */ | |
1741 | if (simple_iv_increment_p (rhs_def_stmt)) | |
1742 | goto dont_fold_assoc; | |
1743 | ||
4ee9c684 | 1744 | /* See if the RHS_DEF_STMT has the same form as our statement. */ |
1745 | if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR) | |
1746 | { | |
1747 | tree rhs_def_rhs = TREE_OPERAND (rhs_def_stmt, 1); | |
1748 | enum tree_code rhs_def_code = TREE_CODE (rhs_def_rhs); | |
1749 | ||
78f29aa3 | 1750 | if ((rhs_code == rhs_def_code && unsafe_associative_fp_binop (rhs)) |
4ee9c684 | 1751 | || (rhs_code == PLUS_EXPR && rhs_def_code == MINUS_EXPR) |
1752 | || (rhs_code == MINUS_EXPR && rhs_def_code == PLUS_EXPR)) | |
1753 | { | |
1754 | tree def_stmt_op0 = TREE_OPERAND (rhs_def_rhs, 0); | |
1755 | tree def_stmt_op1 = TREE_OPERAND (rhs_def_rhs, 1); | |
1756 | ||
1757 | if (TREE_CODE (def_stmt_op0) == SSA_NAME | |
1758 | && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def_stmt_op0) | |
1759 | && is_gimple_min_invariant (def_stmt_op1)) | |
1760 | { | |
1761 | tree outer_const = TREE_OPERAND (rhs, 1); | |
1762 | tree type = TREE_TYPE (TREE_OPERAND (stmt, 0)); | |
1763 | tree t; | |
1764 | ||
fc34d0d0 | 1765 | /* If we care about correct floating point results, then |
1766 | don't fold x + c1 - c2. Note that we need to take both | |
1767 | the codes and the signs to figure this out. */ | |
1768 | if (FLOAT_TYPE_P (type) | |
1769 | && !flag_unsafe_math_optimizations | |
1770 | && (rhs_def_code == PLUS_EXPR | |
1771 | || rhs_def_code == MINUS_EXPR)) | |
1772 | { | |
1773 | bool neg = false; | |
1774 | ||
1775 | neg ^= (rhs_code == MINUS_EXPR); | |
1776 | neg ^= (rhs_def_code == MINUS_EXPR); | |
1777 | neg ^= real_isneg (TREE_REAL_CST_PTR (outer_const)); | |
1778 | neg ^= real_isneg (TREE_REAL_CST_PTR (def_stmt_op1)); | |
1779 | ||
1780 | if (neg) | |
1781 | goto dont_fold_assoc; | |
1782 | } | |
1783 | ||
4ee9c684 | 1784 | /* Ho hum. So fold will only operate on the outermost |
1785 | thingy that we give it, so we have to build the new | |
1786 | expression in two pieces. This requires that we handle | |
1787 | combinations of plus and minus. */ | |
1788 | if (rhs_def_code != rhs_code) | |
1789 | { | |
1790 | if (rhs_def_code == MINUS_EXPR) | |
1791 | t = build (MINUS_EXPR, type, outer_const, def_stmt_op1); | |
1792 | else | |
1793 | t = build (MINUS_EXPR, type, def_stmt_op1, outer_const); | |
1794 | rhs_code = PLUS_EXPR; | |
1795 | } | |
1796 | else if (rhs_def_code == MINUS_EXPR) | |
1797 | t = build (PLUS_EXPR, type, def_stmt_op1, outer_const); | |
1798 | else | |
1799 | t = build (rhs_def_code, type, def_stmt_op1, outer_const); | |
1800 | t = local_fold (t); | |
1801 | t = build (rhs_code, type, def_stmt_op0, t); | |
1802 | t = local_fold (t); | |
1803 | ||
1804 | /* If the result is a suitable looking gimple expression, | |
1805 | then use it instead of the original for STMT. */ | |
1806 | if (TREE_CODE (t) == SSA_NAME | |
ce45a448 | 1807 | || (UNARY_CLASS_P (t) |
4ee9c684 | 1808 | && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME) |
ce45a448 | 1809 | || ((BINARY_CLASS_P (t) || COMPARISON_CLASS_P (t)) |
4ee9c684 | 1810 | && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME |
1811 | && is_gimple_val (TREE_OPERAND (t, 1)))) | |
9c629f0e | 1812 | result = update_rhs_and_lookup_avail_expr (stmt, t, insert); |
4ee9c684 | 1813 | } |
1814 | } | |
1815 | } | |
fc34d0d0 | 1816 | dont_fold_assoc:; |
4ee9c684 | 1817 | } |
1818 | ||
1819 | /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR | |
1820 | and BIT_AND_EXPR respectively if the first operand is greater | |
1821 | than zero and the second operand is an exact power of two. */ | |
1822 | if ((rhs_code == TRUNC_DIV_EXPR || rhs_code == TRUNC_MOD_EXPR) | |
1823 | && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0))) | |
1824 | && integer_pow2p (TREE_OPERAND (rhs, 1))) | |
1825 | { | |
1826 | tree val; | |
1827 | tree op = TREE_OPERAND (rhs, 0); | |
1828 | ||
1829 | if (TYPE_UNSIGNED (TREE_TYPE (op))) | |
1830 | { | |
1831 | val = integer_one_node; | |
1832 | } | |
1833 | else | |
1834 | { | |
1835 | tree dummy_cond = walk_data->global_data; | |
1836 | ||
1837 | if (! dummy_cond) | |
1838 | { | |
1839 | dummy_cond = build (GT_EXPR, boolean_type_node, | |
1840 | op, integer_zero_node); | |
1841 | dummy_cond = build (COND_EXPR, void_type_node, | |
1842 | dummy_cond, NULL, NULL); | |
1843 | walk_data->global_data = dummy_cond; | |
1844 | } | |
1845 | else | |
1846 | { | |
58f52dd4 | 1847 | TREE_SET_CODE (COND_EXPR_COND (dummy_cond), GT_EXPR); |
1848 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op; | |
1849 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1) | |
4ee9c684 | 1850 | = integer_zero_node; |
1851 | } | |
9c629f0e | 1852 | val = simplify_cond_and_lookup_avail_expr (dummy_cond, NULL, false); |
4ee9c684 | 1853 | } |
1854 | ||
1855 | if (val && integer_onep (val)) | |
1856 | { | |
1857 | tree t; | |
1858 | tree op0 = TREE_OPERAND (rhs, 0); | |
1859 | tree op1 = TREE_OPERAND (rhs, 1); | |
1860 | ||
1861 | if (rhs_code == TRUNC_DIV_EXPR) | |
1862 | t = build (RSHIFT_EXPR, TREE_TYPE (op0), op0, | |
7016c612 | 1863 | build_int_cst (NULL_TREE, tree_log2 (op1))); |
4ee9c684 | 1864 | else |
1865 | t = build (BIT_AND_EXPR, TREE_TYPE (op0), op0, | |
1866 | local_fold (build (MINUS_EXPR, TREE_TYPE (op1), | |
1867 | op1, integer_one_node))); | |
1868 | ||
9c629f0e | 1869 | result = update_rhs_and_lookup_avail_expr (stmt, t, insert); |
4ee9c684 | 1870 | } |
1871 | } | |
1872 | ||
1873 | /* Transform ABS (X) into X or -X as appropriate. */ | |
1874 | if (rhs_code == ABS_EXPR | |
1875 | && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))) | |
1876 | { | |
1877 | tree val; | |
1878 | tree op = TREE_OPERAND (rhs, 0); | |
1879 | tree type = TREE_TYPE (op); | |
1880 | ||
1881 | if (TYPE_UNSIGNED (type)) | |
1882 | { | |
1883 | val = integer_zero_node; | |
1884 | } | |
1885 | else | |
1886 | { | |
1887 | tree dummy_cond = walk_data->global_data; | |
1888 | ||
1889 | if (! dummy_cond) | |
1890 | { | |
9fb994de | 1891 | dummy_cond = build (LE_EXPR, boolean_type_node, |
4ee9c684 | 1892 | op, integer_zero_node); |
1893 | dummy_cond = build (COND_EXPR, void_type_node, | |
1894 | dummy_cond, NULL, NULL); | |
1895 | walk_data->global_data = dummy_cond; | |
1896 | } | |
1897 | else | |
1898 | { | |
58f52dd4 | 1899 | TREE_SET_CODE (COND_EXPR_COND (dummy_cond), LE_EXPR); |
1900 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op; | |
1901 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1) | |
779b4c41 | 1902 | = build_int_cst (type, 0); |
4ee9c684 | 1903 | } |
9c629f0e | 1904 | val = simplify_cond_and_lookup_avail_expr (dummy_cond, NULL, false); |
9fb994de | 1905 | |
1906 | if (!val) | |
1907 | { | |
58f52dd4 | 1908 | TREE_SET_CODE (COND_EXPR_COND (dummy_cond), GE_EXPR); |
1909 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 0) = op; | |
1910 | TREE_OPERAND (COND_EXPR_COND (dummy_cond), 1) | |
779b4c41 | 1911 | = build_int_cst (type, 0); |
9fb994de | 1912 | |
1913 | val = simplify_cond_and_lookup_avail_expr (dummy_cond, | |
9fb994de | 1914 | NULL, false); |
1915 | ||
1916 | if (val) | |
1917 | { | |
1918 | if (integer_zerop (val)) | |
1919 | val = integer_one_node; | |
1920 | else if (integer_onep (val)) | |
1921 | val = integer_zero_node; | |
1922 | } | |
1923 | } | |
4ee9c684 | 1924 | } |
1925 | ||
1926 | if (val | |
1927 | && (integer_onep (val) || integer_zerop (val))) | |
1928 | { | |
1929 | tree t; | |
1930 | ||
1931 | if (integer_onep (val)) | |
1932 | t = build1 (NEGATE_EXPR, TREE_TYPE (op), op); | |
1933 | else | |
1934 | t = op; | |
1935 | ||
9c629f0e | 1936 | result = update_rhs_and_lookup_avail_expr (stmt, t, insert); |
4ee9c684 | 1937 | } |
1938 | } | |
1939 | ||
1940 | /* Optimize *"foo" into 'f'. This is done here rather than | |
1941 | in fold to avoid problems with stuff like &*"foo". */ | |
1942 | if (TREE_CODE (rhs) == INDIRECT_REF || TREE_CODE (rhs) == ARRAY_REF) | |
1943 | { | |
1944 | tree t = fold_read_from_constant_string (rhs); | |
1945 | ||
1946 | if (t) | |
9c629f0e | 1947 | result = update_rhs_and_lookup_avail_expr (stmt, t, insert); |
4ee9c684 | 1948 | } |
1949 | ||
1950 | return result; | |
1951 | } | |
1952 | ||
1953 | /* COND is a condition of the form: | |
1954 | ||
1955 | x == const or x != const | |
1956 | ||
1957 | Look back to x's defining statement and see if x is defined as | |
1958 | ||
1959 | x = (type) y; | |
1960 | ||
1961 | If const is unchanged if we convert it to type, then we can build | |
1962 | the equivalent expression: | |
1963 | ||
1964 | ||
1965 | y == const or y != const | |
1966 | ||
1967 | Which may allow further optimizations. | |
1968 | ||
1969 | Return the equivalent comparison or NULL if no such equivalent comparison | |
1970 | was found. */ | |
1971 | ||
1972 | static tree | |
1973 | find_equivalent_equality_comparison (tree cond) | |
1974 | { | |
1975 | tree op0 = TREE_OPERAND (cond, 0); | |
1976 | tree op1 = TREE_OPERAND (cond, 1); | |
1977 | tree def_stmt = SSA_NAME_DEF_STMT (op0); | |
1978 | ||
1979 | /* OP0 might have been a parameter, so first make sure it | |
1980 | was defined by a MODIFY_EXPR. */ | |
1981 | if (def_stmt && TREE_CODE (def_stmt) == MODIFY_EXPR) | |
1982 | { | |
1983 | tree def_rhs = TREE_OPERAND (def_stmt, 1); | |
1984 | ||
1985 | /* Now make sure the RHS of the MODIFY_EXPR is a typecast. */ | |
1986 | if ((TREE_CODE (def_rhs) == NOP_EXPR | |
1987 | || TREE_CODE (def_rhs) == CONVERT_EXPR) | |
1988 | && TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME) | |
1989 | { | |
1990 | tree def_rhs_inner = TREE_OPERAND (def_rhs, 0); | |
1991 | tree def_rhs_inner_type = TREE_TYPE (def_rhs_inner); | |
1992 | tree new; | |
1993 | ||
1994 | if (TYPE_PRECISION (def_rhs_inner_type) | |
1995 | > TYPE_PRECISION (TREE_TYPE (def_rhs))) | |
1996 | return NULL; | |
1997 | ||
1998 | /* What we want to prove is that if we convert OP1 to | |
1999 | the type of the object inside the NOP_EXPR that the | |
2000 | result is still equivalent to SRC. | |
2001 | ||
2002 | If that is true, the build and return new equivalent | |
2003 | condition which uses the source of the typecast and the | |
2004 | new constant (which has only changed its type). */ | |
2005 | new = build1 (TREE_CODE (def_rhs), def_rhs_inner_type, op1); | |
2006 | new = local_fold (new); | |
2007 | if (is_gimple_val (new) && tree_int_cst_equal (new, op1)) | |
2008 | return build (TREE_CODE (cond), TREE_TYPE (cond), | |
2009 | def_rhs_inner, new); | |
2010 | } | |
2011 | } | |
2012 | return NULL; | |
2013 | } | |
2014 | ||
2015 | /* STMT is a COND_EXPR for which we could not trivially determine its | |
2016 | result. This routine attempts to find equivalent forms of the | |
2017 | condition which we may be able to optimize better. It also | |
2018 | uses simple value range propagation to optimize conditionals. */ | |
2019 | ||
2020 | static tree | |
2021 | simplify_cond_and_lookup_avail_expr (tree stmt, | |
4ee9c684 | 2022 | stmt_ann_t ann, |
2023 | int insert) | |
2024 | { | |
2025 | tree cond = COND_EXPR_COND (stmt); | |
2026 | ||
ce45a448 | 2027 | if (COMPARISON_CLASS_P (cond)) |
4ee9c684 | 2028 | { |
2029 | tree op0 = TREE_OPERAND (cond, 0); | |
2030 | tree op1 = TREE_OPERAND (cond, 1); | |
2031 | ||
2032 | if (TREE_CODE (op0) == SSA_NAME && is_gimple_min_invariant (op1)) | |
2033 | { | |
2034 | int limit; | |
2035 | tree low, high, cond_low, cond_high; | |
2036 | int lowequal, highequal, swapped, no_overlap, subset, cond_inverted; | |
2037 | varray_type vrp_records; | |
2038 | struct vrp_element *element; | |
de29fdfe | 2039 | struct vrp_hash_elt vrp_hash_elt, *vrp_hash_elt_p; |
d0d897b6 | 2040 | void **slot; |
4ee9c684 | 2041 | |
2042 | /* First see if we have test of an SSA_NAME against a constant | |
2043 | where the SSA_NAME is defined by an earlier typecast which | |
2044 | is irrelevant when performing tests against the given | |
2045 | constant. */ | |
2046 | if (TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR) | |
2047 | { | |
2048 | tree new_cond = find_equivalent_equality_comparison (cond); | |
2049 | ||
2050 | if (new_cond) | |
2051 | { | |
2052 | /* Update the statement to use the new equivalent | |
2053 | condition. */ | |
2054 | COND_EXPR_COND (stmt) = new_cond; | |
ac4bd4cc | 2055 | |
2056 | /* If this is not a real stmt, ann will be NULL and we | |
2057 | avoid processing the operands. */ | |
2058 | if (ann) | |
22aa74c4 | 2059 | mark_stmt_modified (stmt); |
4ee9c684 | 2060 | |
2061 | /* Lookup the condition and return its known value if it | |
2062 | exists. */ | |
9c629f0e | 2063 | new_cond = lookup_avail_expr (stmt, insert); |
4ee9c684 | 2064 | if (new_cond) |
2065 | return new_cond; | |
2066 | ||
2067 | /* The operands have changed, so update op0 and op1. */ | |
2068 | op0 = TREE_OPERAND (cond, 0); | |
2069 | op1 = TREE_OPERAND (cond, 1); | |
2070 | } | |
2071 | } | |
2072 | ||
2073 | /* Consult the value range records for this variable (if they exist) | |
2074 | to see if we can eliminate or simplify this conditional. | |
2075 | ||
2076 | Note two tests are necessary to determine no records exist. | |
2077 | First we have to see if the virtual array exists, if it | |
2078 | exists, then we have to check its active size. | |
2079 | ||
2080 | Also note the vast majority of conditionals are not testing | |
2081 | a variable which has had its range constrained by an earlier | |
2082 | conditional. So this filter avoids a lot of unnecessary work. */ | |
d0d897b6 | 2083 | vrp_hash_elt.var = op0; |
2084 | vrp_hash_elt.records = NULL; | |
2085 | slot = htab_find_slot (vrp_data, &vrp_hash_elt, NO_INSERT); | |
2086 | if (slot == NULL) | |
2087 | return NULL; | |
2088 | ||
de29fdfe | 2089 | vrp_hash_elt_p = (struct vrp_hash_elt *) *slot; |
2090 | vrp_records = vrp_hash_elt_p->records; | |
4ee9c684 | 2091 | if (vrp_records == NULL) |
2092 | return NULL; | |
2093 | ||
2094 | limit = VARRAY_ACTIVE_SIZE (vrp_records); | |
2095 | ||
2096 | /* If we have no value range records for this variable, or we are | |
2097 | unable to extract a range for this condition, then there is | |
2098 | nothing to do. */ | |
2099 | if (limit == 0 | |
2100 | || ! extract_range_from_cond (cond, &cond_high, | |
2101 | &cond_low, &cond_inverted)) | |
2102 | return NULL; | |
2103 | ||
2104 | /* We really want to avoid unnecessary computations of range | |
2105 | info. So all ranges are computed lazily; this avoids a | |
0c6d8c36 | 2106 | lot of unnecessary work. i.e., we record the conditional, |
4ee9c684 | 2107 | but do not process how it constrains the variable's |
2108 | potential values until we know that processing the condition | |
2109 | could be helpful. | |
2110 | ||
2111 | However, we do not want to have to walk a potentially long | |
2112 | list of ranges, nor do we want to compute a variable's | |
2113 | range more than once for a given path. | |
2114 | ||
2115 | Luckily, each time we encounter a conditional that can not | |
2116 | be otherwise optimized we will end up here and we will | |
2117 | compute the necessary range information for the variable | |
2118 | used in this condition. | |
2119 | ||
2120 | Thus you can conclude that there will never be more than one | |
2121 | conditional associated with a variable which has not been | |
2122 | processed. So we never need to merge more than one new | |
2123 | conditional into the current range. | |
2124 | ||
2125 | These properties also help us avoid unnecessary work. */ | |
2126 | element | |
2127 | = (struct vrp_element *)VARRAY_GENERIC_PTR (vrp_records, limit - 1); | |
2128 | ||
2129 | if (element->high && element->low) | |
2130 | { | |
2131 | /* The last element has been processed, so there is no range | |
2132 | merging to do, we can simply use the high/low values | |
2133 | recorded in the last element. */ | |
2134 | low = element->low; | |
2135 | high = element->high; | |
2136 | } | |
2137 | else | |
2138 | { | |
2139 | tree tmp_high, tmp_low; | |
2140 | int dummy; | |
2141 | ||
c46a7a9f | 2142 | /* The last element has not been processed. Process it now. |
2143 | record_range should ensure for cond inverted is not set. | |
2144 | This call can only fail if cond is x < min or x > max, | |
2145 | which fold should have optimized into false. | |
2146 | If that doesn't happen, just pretend all values are | |
2147 | in the range. */ | |
2148 | if (! extract_range_from_cond (element->cond, &tmp_high, | |
2149 | &tmp_low, &dummy)) | |
2150 | gcc_unreachable (); | |
2151 | else | |
2152 | gcc_assert (dummy == 0); | |
2153 | ||
4ee9c684 | 2154 | /* If this is the only element, then no merging is necessary, |
2155 | the high/low values from extract_range_from_cond are all | |
2156 | we need. */ | |
2157 | if (limit == 1) | |
2158 | { | |
2159 | low = tmp_low; | |
2160 | high = tmp_high; | |
2161 | } | |
2162 | else | |
2163 | { | |
2164 | /* Get the high/low value from the previous element. */ | |
2165 | struct vrp_element *prev | |
2166 | = (struct vrp_element *)VARRAY_GENERIC_PTR (vrp_records, | |
2167 | limit - 2); | |
2168 | low = prev->low; | |
2169 | high = prev->high; | |
2170 | ||
2171 | /* Merge in this element's range with the range from the | |
2172 | previous element. | |
2173 | ||
2174 | The low value for the merged range is the maximum of | |
2175 | the previous low value and the low value of this record. | |
2176 | ||
2177 | Similarly the high value for the merged range is the | |
2178 | minimum of the previous high value and the high value of | |
2179 | this record. */ | |
88dbf20f | 2180 | low = (low && tree_int_cst_compare (low, tmp_low) == 1 |
4ee9c684 | 2181 | ? low : tmp_low); |
88dbf20f | 2182 | high = (high && tree_int_cst_compare (high, tmp_high) == -1 |
4ee9c684 | 2183 | ? high : tmp_high); |
2184 | } | |
2185 | ||
2186 | /* And record the computed range. */ | |
2187 | element->low = low; | |
2188 | element->high = high; | |
2189 | ||
2190 | } | |
2191 | ||
2192 | /* After we have constrained this variable's potential values, | |
2193 | we try to determine the result of the given conditional. | |
2194 | ||
2195 | To simplify later tests, first determine if the current | |
2196 | low value is the same low value as the conditional. | |
2197 | Similarly for the current high value and the high value | |
2198 | for the conditional. */ | |
2199 | lowequal = tree_int_cst_equal (low, cond_low); | |
2200 | highequal = tree_int_cst_equal (high, cond_high); | |
2201 | ||
2202 | if (lowequal && highequal) | |
2203 | return (cond_inverted ? boolean_false_node : boolean_true_node); | |
2204 | ||
2205 | /* To simplify the overlap/subset tests below we may want | |
2206 | to swap the two ranges so that the larger of the two | |
2207 | ranges occurs "first". */ | |
2208 | swapped = 0; | |
2209 | if (tree_int_cst_compare (low, cond_low) == 1 | |
2210 | || (lowequal | |
2211 | && tree_int_cst_compare (cond_high, high) == 1)) | |
2212 | { | |
2213 | tree temp; | |
2214 | ||
2215 | swapped = 1; | |
2216 | temp = low; | |
2217 | low = cond_low; | |
2218 | cond_low = temp; | |
2219 | temp = high; | |
2220 | high = cond_high; | |
2221 | cond_high = temp; | |
2222 | } | |
2223 | ||
2224 | /* Now determine if there is no overlap in the ranges | |
2225 | or if the second range is a subset of the first range. */ | |
2226 | no_overlap = tree_int_cst_lt (high, cond_low); | |
2227 | subset = tree_int_cst_compare (cond_high, high) != 1; | |
2228 | ||
2229 | /* If there was no overlap in the ranges, then this conditional | |
2230 | always has a false value (unless we had to invert this | |
2231 | conditional, in which case it always has a true value). */ | |
2232 | if (no_overlap) | |
2233 | return (cond_inverted ? boolean_true_node : boolean_false_node); | |
2234 | ||
2235 | /* If the current range is a subset of the condition's range, | |
2236 | then this conditional always has a true value (unless we | |
2237 | had to invert this conditional, in which case it always | |
2238 | has a true value). */ | |
2239 | if (subset && swapped) | |
2240 | return (cond_inverted ? boolean_false_node : boolean_true_node); | |
2241 | ||
2242 | /* We were unable to determine the result of the conditional. | |
2243 | However, we may be able to simplify the conditional. First | |
2244 | merge the ranges in the same manner as range merging above. */ | |
2245 | low = tree_int_cst_compare (low, cond_low) == 1 ? low : cond_low; | |
2246 | high = tree_int_cst_compare (high, cond_high) == -1 ? high : cond_high; | |
2247 | ||
2248 | /* If the range has converged to a single point, then turn this | |
2249 | into an equality comparison. */ | |
2250 | if (TREE_CODE (cond) != EQ_EXPR | |
2251 | && TREE_CODE (cond) != NE_EXPR | |
2252 | && tree_int_cst_equal (low, high)) | |
2253 | { | |
2254 | TREE_SET_CODE (cond, EQ_EXPR); | |
2255 | TREE_OPERAND (cond, 1) = high; | |
2256 | } | |
2257 | } | |
2258 | } | |
2259 | return 0; | |
2260 | } | |
2261 | ||
2262 | /* STMT is a SWITCH_EXPR for which we could not trivially determine its | |
2263 | result. This routine attempts to find equivalent forms of the | |
2264 | condition which we may be able to optimize better. */ | |
2265 | ||
2266 | static tree | |
9c629f0e | 2267 | simplify_switch_and_lookup_avail_expr (tree stmt, int insert) |
4ee9c684 | 2268 | { |
2269 | tree cond = SWITCH_COND (stmt); | |
2270 | tree def, to, ti; | |
2271 | ||
2272 | /* The optimization that we really care about is removing unnecessary | |
2273 | casts. That will let us do much better in propagating the inferred | |
2274 | constant at the switch target. */ | |
2275 | if (TREE_CODE (cond) == SSA_NAME) | |
2276 | { | |
2277 | def = SSA_NAME_DEF_STMT (cond); | |
2278 | if (TREE_CODE (def) == MODIFY_EXPR) | |
2279 | { | |
2280 | def = TREE_OPERAND (def, 1); | |
2281 | if (TREE_CODE (def) == NOP_EXPR) | |
2282 | { | |
4739ef9a | 2283 | int need_precision; |
2284 | bool fail; | |
2285 | ||
4ee9c684 | 2286 | def = TREE_OPERAND (def, 0); |
4739ef9a | 2287 | |
2288 | #ifdef ENABLE_CHECKING | |
2289 | /* ??? Why was Jeff testing this? We are gimple... */ | |
8c0963c4 | 2290 | gcc_assert (is_gimple_val (def)); |
4739ef9a | 2291 | #endif |
2292 | ||
4ee9c684 | 2293 | to = TREE_TYPE (cond); |
2294 | ti = TREE_TYPE (def); | |
2295 | ||
4739ef9a | 2296 | /* If we have an extension that preserves value, then we |
4ee9c684 | 2297 | can copy the source value into the switch. */ |
4739ef9a | 2298 | |
2299 | need_precision = TYPE_PRECISION (ti); | |
2300 | fail = false; | |
2301 | if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti)) | |
2302 | fail = true; | |
2303 | else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti)) | |
2304 | need_precision += 1; | |
2305 | if (TYPE_PRECISION (to) < need_precision) | |
2306 | fail = true; | |
2307 | ||
2308 | if (!fail) | |
4ee9c684 | 2309 | { |
2310 | SWITCH_COND (stmt) = def; | |
22aa74c4 | 2311 | mark_stmt_modified (stmt); |
4ee9c684 | 2312 | |
9c629f0e | 2313 | return lookup_avail_expr (stmt, insert); |
4ee9c684 | 2314 | } |
2315 | } | |
2316 | } | |
2317 | } | |
2318 | ||
2319 | return 0; | |
2320 | } | |
2321 | ||
591c2a30 | 2322 | |
2323 | /* CONST_AND_COPIES is a table which maps an SSA_NAME to the current | |
2324 | known value for that SSA_NAME (or NULL if no value is known). | |
2325 | ||
2326 | NONZERO_VARS is the set SSA_NAMES known to have a nonzero value, | |
2327 | even if we don't know their precise value. | |
2328 | ||
2329 | Propagate values from CONST_AND_COPIES and NONZERO_VARS into the PHI | |
2330 | nodes of the successors of BB. */ | |
2331 | ||
2332 | static void | |
fa0f49c6 | 2333 | cprop_into_successor_phis (basic_block bb, bitmap nonzero_vars) |
591c2a30 | 2334 | { |
2335 | edge e; | |
cd665a06 | 2336 | edge_iterator ei; |
591c2a30 | 2337 | |
cd665a06 | 2338 | FOR_EACH_EDGE (e, ei, bb->succs) |
591c2a30 | 2339 | { |
2340 | tree phi; | |
5f50f9bf | 2341 | int indx; |
591c2a30 | 2342 | |
2343 | /* If this is an abnormal edge, then we do not want to copy propagate | |
2344 | into the PHI alternative associated with this edge. */ | |
2345 | if (e->flags & EDGE_ABNORMAL) | |
2346 | continue; | |
2347 | ||
2348 | phi = phi_nodes (e->dest); | |
2349 | if (! phi) | |
2350 | continue; | |
2351 | ||
5f50f9bf | 2352 | indx = e->dest_idx; |
591c2a30 | 2353 | for ( ; phi; phi = PHI_CHAIN (phi)) |
2354 | { | |
591c2a30 | 2355 | tree new; |
2356 | use_operand_p orig_p; | |
2357 | tree orig; | |
2358 | ||
591c2a30 | 2359 | /* The alternative may be associated with a constant, so verify |
2360 | it is an SSA_NAME before doing anything with it. */ | |
5f50f9bf | 2361 | orig_p = PHI_ARG_DEF_PTR (phi, indx); |
591c2a30 | 2362 | orig = USE_FROM_PTR (orig_p); |
2363 | if (TREE_CODE (orig) != SSA_NAME) | |
2364 | continue; | |
2365 | ||
2366 | /* If the alternative is known to have a nonzero value, record | |
2367 | that fact in the PHI node itself for future use. */ | |
2368 | if (bitmap_bit_p (nonzero_vars, SSA_NAME_VERSION (orig))) | |
5f50f9bf | 2369 | PHI_ARG_NONZERO (phi, indx) = true; |
591c2a30 | 2370 | |
2371 | /* If we have *ORIG_P in our constant/copy table, then replace | |
2372 | ORIG_P with its value in our constant/copy table. */ | |
4c7a0518 | 2373 | new = SSA_NAME_VALUE (orig); |
591c2a30 | 2374 | if (new |
88dbf20f | 2375 | && new != orig |
591c2a30 | 2376 | && (TREE_CODE (new) == SSA_NAME |
2377 | || is_gimple_min_invariant (new)) | |
2378 | && may_propagate_copy (orig, new)) | |
88dbf20f | 2379 | propagate_value (orig_p, new); |
591c2a30 | 2380 | } |
2381 | } | |
2382 | } | |
2383 | ||
2f0993e7 | 2384 | /* We have finished optimizing BB, record any information implied by |
2385 | taking a specific outgoing edge from BB. */ | |
2386 | ||
2387 | static void | |
2388 | record_edge_info (basic_block bb) | |
2389 | { | |
2390 | block_stmt_iterator bsi = bsi_last (bb); | |
2391 | struct edge_info *edge_info; | |
2392 | ||
2393 | if (! bsi_end_p (bsi)) | |
2394 | { | |
2395 | tree stmt = bsi_stmt (bsi); | |
2396 | ||
2397 | if (stmt && TREE_CODE (stmt) == SWITCH_EXPR) | |
2398 | { | |
2399 | tree cond = SWITCH_COND (stmt); | |
2400 | ||
2401 | if (TREE_CODE (cond) == SSA_NAME) | |
2402 | { | |
2403 | tree labels = SWITCH_LABELS (stmt); | |
2404 | int i, n_labels = TREE_VEC_LENGTH (labels); | |
2405 | tree *info = xcalloc (n_basic_blocks, sizeof (tree)); | |
2406 | edge e; | |
2407 | edge_iterator ei; | |
2408 | ||
2409 | for (i = 0; i < n_labels; i++) | |
2410 | { | |
2411 | tree label = TREE_VEC_ELT (labels, i); | |
2412 | basic_block target_bb = label_to_block (CASE_LABEL (label)); | |
2413 | ||
2414 | if (CASE_HIGH (label) | |
2415 | || !CASE_LOW (label) | |
2416 | || info[target_bb->index]) | |
2417 | info[target_bb->index] = error_mark_node; | |
2418 | else | |
2419 | info[target_bb->index] = label; | |
2420 | } | |
2421 | ||
2422 | FOR_EACH_EDGE (e, ei, bb->succs) | |
2423 | { | |
2424 | basic_block target_bb = e->dest; | |
2425 | tree node = info[target_bb->index]; | |
591c2a30 | 2426 | |
2f0993e7 | 2427 | if (node != NULL && node != error_mark_node) |
2428 | { | |
2429 | tree x = fold_convert (TREE_TYPE (cond), CASE_LOW (node)); | |
2430 | edge_info = allocate_edge_info (e); | |
2431 | edge_info->lhs = cond; | |
2432 | edge_info->rhs = x; | |
2433 | } | |
2434 | } | |
2435 | free (info); | |
2436 | } | |
2437 | } | |
2438 | ||
2439 | /* A COND_EXPR may create equivalences too. */ | |
2440 | if (stmt && TREE_CODE (stmt) == COND_EXPR) | |
2441 | { | |
2442 | tree cond = COND_EXPR_COND (stmt); | |
2443 | edge true_edge; | |
2444 | edge false_edge; | |
2445 | ||
2446 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
2447 | ||
640e9781 | 2448 | /* If the conditional is a single variable 'X', record 'X = 1' |
2f0993e7 | 2449 | for the true edge and 'X = 0' on the false edge. */ |
2450 | if (SSA_VAR_P (cond)) | |
2451 | { | |
2452 | struct edge_info *edge_info; | |
2453 | ||
2454 | edge_info = allocate_edge_info (true_edge); | |
2455 | edge_info->lhs = cond; | |
2456 | edge_info->rhs = constant_boolean_node (1, TREE_TYPE (cond)); | |
2457 | ||
2458 | edge_info = allocate_edge_info (false_edge); | |
2459 | edge_info->lhs = cond; | |
2460 | edge_info->rhs = constant_boolean_node (0, TREE_TYPE (cond)); | |
2461 | } | |
2462 | /* Equality tests may create one or two equivalences. */ | |
2463 | else if (COMPARISON_CLASS_P (cond)) | |
2464 | { | |
2465 | tree op0 = TREE_OPERAND (cond, 0); | |
2466 | tree op1 = TREE_OPERAND (cond, 1); | |
2467 | ||
2468 | /* Special case comparing booleans against a constant as we | |
2469 | know the value of OP0 on both arms of the branch. i.e., we | |
2470 | can record an equivalence for OP0 rather than COND. */ | |
2471 | if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR) | |
2472 | && TREE_CODE (op0) == SSA_NAME | |
2473 | && TREE_CODE (TREE_TYPE (op0)) == BOOLEAN_TYPE | |
2474 | && is_gimple_min_invariant (op1)) | |
2475 | { | |
2476 | if (TREE_CODE (cond) == EQ_EXPR) | |
2477 | { | |
2478 | edge_info = allocate_edge_info (true_edge); | |
2479 | edge_info->lhs = op0; | |
2480 | edge_info->rhs = (integer_zerop (op1) | |
2481 | ? boolean_false_node | |
2482 | : boolean_true_node); | |
2483 | ||
2484 | edge_info = allocate_edge_info (false_edge); | |
2485 | edge_info->lhs = op0; | |
2486 | edge_info->rhs = (integer_zerop (op1) | |
2487 | ? boolean_true_node | |
2488 | : boolean_false_node); | |
2489 | } | |
2490 | else | |
2491 | { | |
2492 | edge_info = allocate_edge_info (true_edge); | |
2493 | edge_info->lhs = op0; | |
2494 | edge_info->rhs = (integer_zerop (op1) | |
2495 | ? boolean_true_node | |
2496 | : boolean_false_node); | |
2497 | ||
2498 | edge_info = allocate_edge_info (false_edge); | |
2499 | edge_info->lhs = op0; | |
2500 | edge_info->rhs = (integer_zerop (op1) | |
2501 | ? boolean_false_node | |
2502 | : boolean_true_node); | |
2503 | } | |
2504 | } | |
2505 | ||
a07a7473 | 2506 | else if (is_gimple_min_invariant (op0) |
2507 | && (TREE_CODE (op1) == SSA_NAME | |
2508 | || is_gimple_min_invariant (op1))) | |
2f0993e7 | 2509 | { |
2510 | tree inverted = invert_truthvalue (cond); | |
2511 | struct edge_info *edge_info; | |
2512 | ||
2513 | edge_info = allocate_edge_info (true_edge); | |
2514 | record_conditions (edge_info, cond, inverted); | |
2515 | ||
2516 | if (TREE_CODE (cond) == EQ_EXPR) | |
2517 | { | |
2518 | edge_info->lhs = op1; | |
2519 | edge_info->rhs = op0; | |
2520 | } | |
2521 | ||
2522 | edge_info = allocate_edge_info (false_edge); | |
2523 | record_conditions (edge_info, inverted, cond); | |
2524 | ||
2525 | if (TREE_CODE (cond) == NE_EXPR) | |
2526 | { | |
2527 | edge_info->lhs = op1; | |
2528 | edge_info->rhs = op0; | |
2529 | } | |
2530 | } | |
2531 | ||
a07a7473 | 2532 | else if (TREE_CODE (op0) == SSA_NAME |
2533 | && (is_gimple_min_invariant (op1) | |
2534 | || TREE_CODE (op1) == SSA_NAME)) | |
2f0993e7 | 2535 | { |
2536 | tree inverted = invert_truthvalue (cond); | |
2537 | struct edge_info *edge_info; | |
2538 | ||
2539 | edge_info = allocate_edge_info (true_edge); | |
2540 | record_conditions (edge_info, cond, inverted); | |
2541 | ||
2542 | if (TREE_CODE (cond) == EQ_EXPR) | |
2543 | { | |
2544 | edge_info->lhs = op0; | |
2545 | edge_info->rhs = op1; | |
2546 | } | |
2547 | ||
2548 | edge_info = allocate_edge_info (false_edge); | |
2549 | record_conditions (edge_info, inverted, cond); | |
2550 | ||
2551 | if (TREE_CODE (cond) == NE_EXPR) | |
2552 | { | |
2553 | edge_info->lhs = op0; | |
2554 | edge_info->rhs = op1; | |
2555 | } | |
2556 | } | |
2557 | } | |
2558 | ||
2559 | /* ??? TRUTH_NOT_EXPR can create an equivalence too. */ | |
2560 | } | |
2561 | } | |
2562 | } | |
2563 | ||
2564 | /* Propagate information from BB to its outgoing edges. | |
2565 | ||
2566 | This can include equivalency information implied by control statements | |
2567 | at the end of BB and const/copy propagation into PHIs in BB's | |
2568 | successor blocks. */ | |
4ee9c684 | 2569 | |
2570 | static void | |
2f0993e7 | 2571 | propagate_to_outgoing_edges (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
2572 | basic_block bb) | |
4ee9c684 | 2573 | { |
2f0993e7 | 2574 | record_edge_info (bb); |
fa0f49c6 | 2575 | cprop_into_successor_phis (bb, nonzero_vars); |
4ee9c684 | 2576 | } |
2577 | ||
2578 | /* Search for redundant computations in STMT. If any are found, then | |
2579 | replace them with the variable holding the result of the computation. | |
2580 | ||
2581 | If safe, record this expression into the available expression hash | |
2582 | table. */ | |
2583 | ||
2584 | static bool | |
2585 | eliminate_redundant_computations (struct dom_walk_data *walk_data, | |
2586 | tree stmt, stmt_ann_t ann) | |
2587 | { | |
4ee9c684 | 2588 | tree *expr_p, def = NULL_TREE; |
2589 | bool insert = true; | |
2590 | tree cached_lhs; | |
2591 | bool retval = false; | |
4ee9c684 | 2592 | |
2593 | if (TREE_CODE (stmt) == MODIFY_EXPR) | |
2594 | def = TREE_OPERAND (stmt, 0); | |
2595 | ||
2596 | /* Certain expressions on the RHS can be optimized away, but can not | |
dac49aa5 | 2597 | themselves be entered into the hash tables. */ |
4ee9c684 | 2598 | if (ann->makes_aliased_stores |
2599 | || ! def | |
2600 | || TREE_CODE (def) != SSA_NAME | |
2601 | || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def) | |
b66731e8 | 2602 | || !ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF) |
119a0489 | 2603 | /* Do not record equivalences for increments of ivs. This would create |
2604 | overlapping live ranges for a very questionable gain. */ | |
2605 | || simple_iv_increment_p (stmt)) | |
4ee9c684 | 2606 | insert = false; |
2607 | ||
2608 | /* Check if the expression has been computed before. */ | |
9c629f0e | 2609 | cached_lhs = lookup_avail_expr (stmt, insert); |
4ee9c684 | 2610 | |
2611 | /* If this is an assignment and the RHS was not in the hash table, | |
2612 | then try to simplify the RHS and lookup the new RHS in the | |
2613 | hash table. */ | |
2614 | if (! cached_lhs && TREE_CODE (stmt) == MODIFY_EXPR) | |
9c629f0e | 2615 | cached_lhs = simplify_rhs_and_lookup_avail_expr (walk_data, stmt, insert); |
4ee9c684 | 2616 | /* Similarly if this is a COND_EXPR and we did not find its |
2617 | expression in the hash table, simplify the condition and | |
2618 | try again. */ | |
2619 | else if (! cached_lhs && TREE_CODE (stmt) == COND_EXPR) | |
9c629f0e | 2620 | cached_lhs = simplify_cond_and_lookup_avail_expr (stmt, ann, insert); |
4ee9c684 | 2621 | /* Similarly for a SWITCH_EXPR. */ |
2622 | else if (!cached_lhs && TREE_CODE (stmt) == SWITCH_EXPR) | |
9c629f0e | 2623 | cached_lhs = simplify_switch_and_lookup_avail_expr (stmt, insert); |
4ee9c684 | 2624 | |
2625 | opt_stats.num_exprs_considered++; | |
2626 | ||
2627 | /* Get a pointer to the expression we are trying to optimize. */ | |
2628 | if (TREE_CODE (stmt) == COND_EXPR) | |
2629 | expr_p = &COND_EXPR_COND (stmt); | |
2630 | else if (TREE_CODE (stmt) == SWITCH_EXPR) | |
2631 | expr_p = &SWITCH_COND (stmt); | |
2632 | else if (TREE_CODE (stmt) == RETURN_EXPR && TREE_OPERAND (stmt, 0)) | |
2633 | expr_p = &TREE_OPERAND (TREE_OPERAND (stmt, 0), 1); | |
2634 | else | |
2635 | expr_p = &TREE_OPERAND (stmt, 1); | |
2636 | ||
2637 | /* It is safe to ignore types here since we have already done | |
2638 | type checking in the hashing and equality routines. In fact | |
2639 | type checking here merely gets in the way of constant | |
2640 | propagation. Also, make sure that it is safe to propagate | |
2641 | CACHED_LHS into *EXPR_P. */ | |
2642 | if (cached_lhs | |
2643 | && (TREE_CODE (cached_lhs) != SSA_NAME | |
591c2a30 | 2644 | || may_propagate_copy (*expr_p, cached_lhs))) |
4ee9c684 | 2645 | { |
2646 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2647 | { | |
2648 | fprintf (dump_file, " Replaced redundant expr '"); | |
2649 | print_generic_expr (dump_file, *expr_p, dump_flags); | |
2650 | fprintf (dump_file, "' with '"); | |
2651 | print_generic_expr (dump_file, cached_lhs, dump_flags); | |
2652 | fprintf (dump_file, "'\n"); | |
2653 | } | |
2654 | ||
2655 | opt_stats.num_re++; | |
2656 | ||
2657 | #if defined ENABLE_CHECKING | |
8c0963c4 | 2658 | gcc_assert (TREE_CODE (cached_lhs) == SSA_NAME |
2659 | || is_gimple_min_invariant (cached_lhs)); | |
4ee9c684 | 2660 | #endif |
2661 | ||
2662 | if (TREE_CODE (cached_lhs) == ADDR_EXPR | |
2663 | || (POINTER_TYPE_P (TREE_TYPE (*expr_p)) | |
2664 | && is_gimple_min_invariant (cached_lhs))) | |
2665 | retval = true; | |
2666 | ||
56004dc5 | 2667 | propagate_tree_value (expr_p, cached_lhs); |
22aa74c4 | 2668 | mark_stmt_modified (stmt); |
4ee9c684 | 2669 | } |
2670 | return retval; | |
2671 | } | |
2672 | ||
2673 | /* STMT, a MODIFY_EXPR, may create certain equivalences, in either | |
2674 | the available expressions table or the const_and_copies table. | |
2675 | Detect and record those equivalences. */ | |
2676 | ||
2677 | static void | |
2678 | record_equivalences_from_stmt (tree stmt, | |
4ee9c684 | 2679 | int may_optimize_p, |
2680 | stmt_ann_t ann) | |
2681 | { | |
2682 | tree lhs = TREE_OPERAND (stmt, 0); | |
2683 | enum tree_code lhs_code = TREE_CODE (lhs); | |
2684 | int i; | |
2685 | ||
2686 | if (lhs_code == SSA_NAME) | |
2687 | { | |
2688 | tree rhs = TREE_OPERAND (stmt, 1); | |
2689 | ||
2690 | /* Strip away any useless type conversions. */ | |
2691 | STRIP_USELESS_TYPE_CONVERSION (rhs); | |
2692 | ||
2693 | /* If the RHS of the assignment is a constant or another variable that | |
2694 | may be propagated, register it in the CONST_AND_COPIES table. We | |
2695 | do not need to record unwind data for this, since this is a true | |
365db11e | 2696 | assignment and not an equivalence inferred from a comparison. All |
4ee9c684 | 2697 | uses of this ssa name are dominated by this assignment, so unwinding |
2698 | just costs time and space. */ | |
2699 | if (may_optimize_p | |
2700 | && (TREE_CODE (rhs) == SSA_NAME | |
2701 | || is_gimple_min_invariant (rhs))) | |
4c7a0518 | 2702 | SSA_NAME_VALUE (lhs) = rhs; |
4ee9c684 | 2703 | |
88dbf20f | 2704 | if (expr_computes_nonzero (rhs)) |
180d0339 | 2705 | record_var_is_nonzero (lhs); |
4ee9c684 | 2706 | } |
2707 | ||
2708 | /* Look at both sides for pointer dereferences. If we find one, then | |
2709 | the pointer must be nonnull and we can enter that equivalence into | |
2710 | the hash tables. */ | |
6e9a4371 | 2711 | if (flag_delete_null_pointer_checks) |
2712 | for (i = 0; i < 2; i++) | |
2713 | { | |
2714 | tree t = TREE_OPERAND (stmt, i); | |
2715 | ||
2716 | /* Strip away any COMPONENT_REFs. */ | |
2717 | while (TREE_CODE (t) == COMPONENT_REF) | |
2718 | t = TREE_OPERAND (t, 0); | |
2719 | ||
2720 | /* Now see if this is a pointer dereference. */ | |
2a448a75 | 2721 | if (INDIRECT_REF_P (t)) |
6e9a4371 | 2722 | { |
2723 | tree op = TREE_OPERAND (t, 0); | |
2724 | ||
2725 | /* If the pointer is a SSA variable, then enter new | |
2726 | equivalences into the hash table. */ | |
2727 | while (TREE_CODE (op) == SSA_NAME) | |
2728 | { | |
2729 | tree def = SSA_NAME_DEF_STMT (op); | |
2730 | ||
180d0339 | 2731 | record_var_is_nonzero (op); |
6e9a4371 | 2732 | |
2733 | /* And walk up the USE-DEF chains noting other SSA_NAMEs | |
2734 | which are known to have a nonzero value. */ | |
2735 | if (def | |
2736 | && TREE_CODE (def) == MODIFY_EXPR | |
2737 | && TREE_CODE (TREE_OPERAND (def, 1)) == NOP_EXPR) | |
2738 | op = TREE_OPERAND (TREE_OPERAND (def, 1), 0); | |
2739 | else | |
2740 | break; | |
2741 | } | |
2742 | } | |
2743 | } | |
4ee9c684 | 2744 | |
2745 | /* A memory store, even an aliased store, creates a useful | |
2746 | equivalence. By exchanging the LHS and RHS, creating suitable | |
2747 | vops and recording the result in the available expression table, | |
2748 | we may be able to expose more redundant loads. */ | |
2749 | if (!ann->has_volatile_ops | |
2750 | && (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME | |
2751 | || is_gimple_min_invariant (TREE_OPERAND (stmt, 1))) | |
2752 | && !is_gimple_reg (lhs)) | |
2753 | { | |
2754 | tree rhs = TREE_OPERAND (stmt, 1); | |
2755 | tree new; | |
4ee9c684 | 2756 | |
2757 | /* FIXME: If the LHS of the assignment is a bitfield and the RHS | |
2758 | is a constant, we need to adjust the constant to fit into the | |
2759 | type of the LHS. If the LHS is a bitfield and the RHS is not | |
2760 | a constant, then we can not record any equivalences for this | |
2761 | statement since we would need to represent the widening or | |
2762 | narrowing of RHS. This fixes gcc.c-torture/execute/921016-1.c | |
2763 | and should not be necessary if GCC represented bitfields | |
2764 | properly. */ | |
2765 | if (lhs_code == COMPONENT_REF | |
2766 | && DECL_BIT_FIELD (TREE_OPERAND (lhs, 1))) | |
2767 | { | |
2768 | if (TREE_CONSTANT (rhs)) | |
2769 | rhs = widen_bitfield (rhs, TREE_OPERAND (lhs, 1), lhs); | |
2770 | else | |
2771 | rhs = NULL; | |
2772 | ||
2773 | /* If the value overflowed, then we can not use this equivalence. */ | |
2774 | if (rhs && ! is_gimple_min_invariant (rhs)) | |
2775 | rhs = NULL; | |
2776 | } | |
2777 | ||
2778 | if (rhs) | |
2779 | { | |
4ee9c684 | 2780 | /* Build a new statement with the RHS and LHS exchanged. */ |
2781 | new = build (MODIFY_EXPR, TREE_TYPE (stmt), rhs, lhs); | |
2782 | ||
b66731e8 | 2783 | create_ssa_artficial_load_stmt (new, stmt); |
4ee9c684 | 2784 | |
2785 | /* Finally enter the statement into the available expression | |
2786 | table. */ | |
9c629f0e | 2787 | lookup_avail_expr (new, true); |
4ee9c684 | 2788 | } |
2789 | } | |
2790 | } | |
2791 | ||
591c2a30 | 2792 | /* Replace *OP_P in STMT with any known equivalent value for *OP_P from |
2793 | CONST_AND_COPIES. */ | |
2794 | ||
2795 | static bool | |
fa0f49c6 | 2796 | cprop_operand (tree stmt, use_operand_p op_p) |
591c2a30 | 2797 | { |
2798 | bool may_have_exposed_new_symbols = false; | |
2799 | tree val; | |
2800 | tree op = USE_FROM_PTR (op_p); | |
2801 | ||
2802 | /* If the operand has a known constant value or it is known to be a | |
2803 | copy of some other variable, use the value or copy stored in | |
2804 | CONST_AND_COPIES. */ | |
4c7a0518 | 2805 | val = SSA_NAME_VALUE (op); |
88dbf20f | 2806 | if (val && val != op && TREE_CODE (val) != VALUE_HANDLE) |
591c2a30 | 2807 | { |
2808 | tree op_type, val_type; | |
2809 | ||
2810 | /* Do not change the base variable in the virtual operand | |
2811 | tables. That would make it impossible to reconstruct | |
2812 | the renamed virtual operand if we later modify this | |
2813 | statement. Also only allow the new value to be an SSA_NAME | |
2814 | for propagation into virtual operands. */ | |
2815 | if (!is_gimple_reg (op) | |
88dbf20f | 2816 | && (TREE_CODE (val) != SSA_NAME |
2817 | || is_gimple_reg (val) | |
2818 | || get_virtual_var (val) != get_virtual_var (op))) | |
591c2a30 | 2819 | return false; |
2820 | ||
93b4f514 | 2821 | /* Do not replace hard register operands in asm statements. */ |
2822 | if (TREE_CODE (stmt) == ASM_EXPR | |
2823 | && !may_propagate_copy_into_asm (op)) | |
2824 | return false; | |
2825 | ||
591c2a30 | 2826 | /* Get the toplevel type of each operand. */ |
2827 | op_type = TREE_TYPE (op); | |
2828 | val_type = TREE_TYPE (val); | |
2829 | ||
2830 | /* While both types are pointers, get the type of the object | |
2831 | pointed to. */ | |
2832 | while (POINTER_TYPE_P (op_type) && POINTER_TYPE_P (val_type)) | |
2833 | { | |
2834 | op_type = TREE_TYPE (op_type); | |
2835 | val_type = TREE_TYPE (val_type); | |
2836 | } | |
2837 | ||
4f7f73c8 | 2838 | /* Make sure underlying types match before propagating a constant by |
2839 | converting the constant to the proper type. Note that convert may | |
2840 | return a non-gimple expression, in which case we ignore this | |
2841 | propagation opportunity. */ | |
2842 | if (TREE_CODE (val) != SSA_NAME) | |
591c2a30 | 2843 | { |
4f7f73c8 | 2844 | if (!lang_hooks.types_compatible_p (op_type, val_type)) |
2845 | { | |
2846 | val = fold_convert (TREE_TYPE (op), val); | |
2847 | if (!is_gimple_min_invariant (val)) | |
2848 | return false; | |
2849 | } | |
591c2a30 | 2850 | } |
2851 | ||
2852 | /* Certain operands are not allowed to be copy propagated due | |
2853 | to their interaction with exception handling and some GCC | |
2854 | extensions. */ | |
4f7f73c8 | 2855 | else if (!may_propagate_copy (op, val)) |
591c2a30 | 2856 | return false; |
652a5bec | 2857 | |
2858 | /* Do not propagate copies if the propagated value is at a deeper loop | |
2859 | depth than the propagatee. Otherwise, this may move loop variant | |
2860 | variables outside of their loops and prevent coalescing | |
2861 | opportunities. If the value was loop invariant, it will be hoisted | |
2862 | by LICM and exposed for copy propagation. */ | |
2863 | if (loop_depth_of_name (val) > loop_depth_of_name (op)) | |
2864 | return false; | |
591c2a30 | 2865 | |
2866 | /* Dump details. */ | |
2867 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2868 | { | |
2869 | fprintf (dump_file, " Replaced '"); | |
2870 | print_generic_expr (dump_file, op, dump_flags); | |
2871 | fprintf (dump_file, "' with %s '", | |
2872 | (TREE_CODE (val) != SSA_NAME ? "constant" : "variable")); | |
2873 | print_generic_expr (dump_file, val, dump_flags); | |
2874 | fprintf (dump_file, "'\n"); | |
2875 | } | |
2876 | ||
2877 | /* If VAL is an ADDR_EXPR or a constant of pointer type, note | |
2878 | that we may have exposed a new symbol for SSA renaming. */ | |
2879 | if (TREE_CODE (val) == ADDR_EXPR | |
2880 | || (POINTER_TYPE_P (TREE_TYPE (op)) | |
2881 | && is_gimple_min_invariant (val))) | |
2882 | may_have_exposed_new_symbols = true; | |
2883 | ||
88dbf20f | 2884 | if (TREE_CODE (val) != SSA_NAME) |
2885 | opt_stats.num_const_prop++; | |
2886 | else | |
2887 | opt_stats.num_copy_prop++; | |
2888 | ||
591c2a30 | 2889 | propagate_value (op_p, val); |
2890 | ||
2891 | /* And note that we modified this statement. This is now | |
2892 | safe, even if we changed virtual operands since we will | |
2893 | rescan the statement and rewrite its operands again. */ | |
22aa74c4 | 2894 | mark_stmt_modified (stmt); |
591c2a30 | 2895 | } |
2896 | return may_have_exposed_new_symbols; | |
2897 | } | |
2898 | ||
2899 | /* CONST_AND_COPIES is a table which maps an SSA_NAME to the current | |
2900 | known value for that SSA_NAME (or NULL if no value is known). | |
2901 | ||
2902 | Propagate values from CONST_AND_COPIES into the uses, vuses and | |
2903 | v_may_def_ops of STMT. */ | |
2904 | ||
2905 | static bool | |
fa0f49c6 | 2906 | cprop_into_stmt (tree stmt) |
591c2a30 | 2907 | { |
2908 | bool may_have_exposed_new_symbols = false; | |
43daa21e | 2909 | use_operand_p op_p; |
2910 | ssa_op_iter iter; | |
591c2a30 | 2911 | |
43daa21e | 2912 | FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_ALL_USES) |
591c2a30 | 2913 | { |
591c2a30 | 2914 | if (TREE_CODE (USE_FROM_PTR (op_p)) == SSA_NAME) |
fa0f49c6 | 2915 | may_have_exposed_new_symbols |= cprop_operand (stmt, op_p); |
591c2a30 | 2916 | } |
2917 | ||
591c2a30 | 2918 | return may_have_exposed_new_symbols; |
2919 | } | |
2920 | ||
2921 | ||
4ee9c684 | 2922 | /* Optimize the statement pointed by iterator SI. |
2923 | ||
2924 | We try to perform some simplistic global redundancy elimination and | |
2925 | constant propagation: | |
2926 | ||
2927 | 1- To detect global redundancy, we keep track of expressions that have | |
2928 | been computed in this block and its dominators. If we find that the | |
2929 | same expression is computed more than once, we eliminate repeated | |
2930 | computations by using the target of the first one. | |
2931 | ||
2932 | 2- Constant values and copy assignments. This is used to do very | |
2933 | simplistic constant and copy propagation. When a constant or copy | |
2934 | assignment is found, we map the value on the RHS of the assignment to | |
2935 | the variable in the LHS in the CONST_AND_COPIES table. */ | |
2936 | ||
2937 | static void | |
35c15734 | 2938 | optimize_stmt (struct dom_walk_data *walk_data, basic_block bb, |
4ee9c684 | 2939 | block_stmt_iterator si) |
2940 | { | |
2941 | stmt_ann_t ann; | |
4c27dd45 | 2942 | tree stmt, old_stmt; |
4ee9c684 | 2943 | bool may_optimize_p; |
2944 | bool may_have_exposed_new_symbols = false; | |
4ee9c684 | 2945 | |
4c27dd45 | 2946 | old_stmt = stmt = bsi_stmt (si); |
4ee9c684 | 2947 | |
22aa74c4 | 2948 | update_stmt_if_modified (stmt); |
4ee9c684 | 2949 | ann = stmt_ann (stmt); |
4ee9c684 | 2950 | opt_stats.num_stmts++; |
2951 | may_have_exposed_new_symbols = false; | |
2952 | ||
2953 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2954 | { | |
2955 | fprintf (dump_file, "Optimizing statement "); | |
2956 | print_generic_stmt (dump_file, stmt, TDF_SLIM); | |
2957 | } | |
2958 | ||
2cf24776 | 2959 | /* Const/copy propagate into USES, VUSES and the RHS of V_MAY_DEFs. */ |
fa0f49c6 | 2960 | may_have_exposed_new_symbols = cprop_into_stmt (stmt); |
4ee9c684 | 2961 | |
2962 | /* If the statement has been modified with constant replacements, | |
2963 | fold its RHS before checking for redundant computations. */ | |
2964 | if (ann->modified) | |
2965 | { | |
f2fae51f | 2966 | tree rhs; |
2967 | ||
4ee9c684 | 2968 | /* Try to fold the statement making sure that STMT is kept |
2969 | up to date. */ | |
2970 | if (fold_stmt (bsi_stmt_ptr (si))) | |
2971 | { | |
2972 | stmt = bsi_stmt (si); | |
2973 | ann = stmt_ann (stmt); | |
2974 | ||
2975 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2976 | { | |
2977 | fprintf (dump_file, " Folded to: "); | |
2978 | print_generic_stmt (dump_file, stmt, TDF_SLIM); | |
2979 | } | |
2980 | } | |
2981 | ||
f2fae51f | 2982 | rhs = get_rhs (stmt); |
2983 | if (rhs && TREE_CODE (rhs) == ADDR_EXPR) | |
2984 | recompute_tree_invarant_for_addr_expr (rhs); | |
2985 | ||
4ee9c684 | 2986 | /* Constant/copy propagation above may change the set of |
2987 | virtual operands associated with this statement. Folding | |
2988 | may remove the need for some virtual operands. | |
2989 | ||
2990 | Indicate we will need to rescan and rewrite the statement. */ | |
2991 | may_have_exposed_new_symbols = true; | |
2992 | } | |
2993 | ||
2994 | /* Check for redundant computations. Do this optimization only | |
2995 | for assignments that have no volatile ops and conditionals. */ | |
2996 | may_optimize_p = (!ann->has_volatile_ops | |
2997 | && ((TREE_CODE (stmt) == RETURN_EXPR | |
2998 | && TREE_OPERAND (stmt, 0) | |
2999 | && TREE_CODE (TREE_OPERAND (stmt, 0)) == MODIFY_EXPR | |
3000 | && ! (TREE_SIDE_EFFECTS | |
3001 | (TREE_OPERAND (TREE_OPERAND (stmt, 0), 1)))) | |
3002 | || (TREE_CODE (stmt) == MODIFY_EXPR | |
3003 | && ! TREE_SIDE_EFFECTS (TREE_OPERAND (stmt, 1))) | |
3004 | || TREE_CODE (stmt) == COND_EXPR | |
3005 | || TREE_CODE (stmt) == SWITCH_EXPR)); | |
3006 | ||
3007 | if (may_optimize_p) | |
3008 | may_have_exposed_new_symbols | |
3009 | |= eliminate_redundant_computations (walk_data, stmt, ann); | |
3010 | ||
3011 | /* Record any additional equivalences created by this statement. */ | |
3012 | if (TREE_CODE (stmt) == MODIFY_EXPR) | |
3013 | record_equivalences_from_stmt (stmt, | |
4ee9c684 | 3014 | may_optimize_p, |
3015 | ann); | |
3016 | ||
4ee9c684 | 3017 | /* If STMT is a COND_EXPR and it was modified, then we may know |
3018 | where it goes. If that is the case, then mark the CFG as altered. | |
3019 | ||
3020 | This will cause us to later call remove_unreachable_blocks and | |
3021 | cleanup_tree_cfg when it is safe to do so. It is not safe to | |
3022 | clean things up here since removal of edges and such can trigger | |
3023 | the removal of PHI nodes, which in turn can release SSA_NAMEs to | |
3024 | the manager. | |
3025 | ||
3026 | That's all fine and good, except that once SSA_NAMEs are released | |
3027 | to the manager, we must not call create_ssa_name until all references | |
3028 | to released SSA_NAMEs have been eliminated. | |
3029 | ||
3030 | All references to the deleted SSA_NAMEs can not be eliminated until | |
3031 | we remove unreachable blocks. | |
3032 | ||
3033 | We can not remove unreachable blocks until after we have completed | |
3034 | any queued jump threading. | |
3035 | ||
3036 | We can not complete any queued jump threads until we have taken | |
3037 | appropriate variables out of SSA form. Taking variables out of | |
3038 | SSA form can call create_ssa_name and thus we lose. | |
3039 | ||
3040 | Ultimately I suspect we're going to need to change the interface | |
3041 | into the SSA_NAME manager. */ | |
3042 | ||
3043 | if (ann->modified) | |
3044 | { | |
3045 | tree val = NULL; | |
3046 | ||
3047 | if (TREE_CODE (stmt) == COND_EXPR) | |
3048 | val = COND_EXPR_COND (stmt); | |
3049 | else if (TREE_CODE (stmt) == SWITCH_EXPR) | |
3050 | val = SWITCH_COND (stmt); | |
3051 | ||
35c15734 | 3052 | if (val && TREE_CODE (val) == INTEGER_CST && find_taken_edge (bb, val)) |
4ee9c684 | 3053 | cfg_altered = true; |
35c15734 | 3054 | |
3055 | /* If we simplified a statement in such a way as to be shown that it | |
3056 | cannot trap, update the eh information and the cfg to match. */ | |
4c27dd45 | 3057 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt)) |
35c15734 | 3058 | { |
3059 | bitmap_set_bit (need_eh_cleanup, bb->index); | |
3060 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3061 | fprintf (dump_file, " Flagged to clear EH edges.\n"); | |
3062 | } | |
4ee9c684 | 3063 | } |
35c15734 | 3064 | |
4ee9c684 | 3065 | if (may_have_exposed_new_symbols) |
046bfc77 | 3066 | VEC_safe_push (tree, heap, stmts_to_rescan, bsi_stmt (si)); |
4ee9c684 | 3067 | } |
3068 | ||
3069 | /* Replace the RHS of STMT with NEW_RHS. If RHS can be found in the | |
3070 | available expression hashtable, then return the LHS from the hash | |
3071 | table. | |
3072 | ||
3073 | If INSERT is true, then we also update the available expression | |
3074 | hash table to account for the changes made to STMT. */ | |
3075 | ||
3076 | static tree | |
9c629f0e | 3077 | update_rhs_and_lookup_avail_expr (tree stmt, tree new_rhs, bool insert) |
4ee9c684 | 3078 | { |
3079 | tree cached_lhs = NULL; | |
3080 | ||
3081 | /* Remove the old entry from the hash table. */ | |
3082 | if (insert) | |
3083 | { | |
3084 | struct expr_hash_elt element; | |
3085 | ||
3086 | initialize_hash_element (stmt, NULL, &element); | |
3087 | htab_remove_elt_with_hash (avail_exprs, &element, element.hash); | |
3088 | } | |
3089 | ||
3090 | /* Now update the RHS of the assignment. */ | |
3091 | TREE_OPERAND (stmt, 1) = new_rhs; | |
3092 | ||
3093 | /* Now lookup the updated statement in the hash table. */ | |
9c629f0e | 3094 | cached_lhs = lookup_avail_expr (stmt, insert); |
4ee9c684 | 3095 | |
3096 | /* We have now called lookup_avail_expr twice with two different | |
3097 | versions of this same statement, once in optimize_stmt, once here. | |
3098 | ||
3099 | We know the call in optimize_stmt did not find an existing entry | |
3100 | in the hash table, so a new entry was created. At the same time | |
f0458177 | 3101 | this statement was pushed onto the AVAIL_EXPRS_STACK vector. |
4ee9c684 | 3102 | |
3103 | If this call failed to find an existing entry on the hash table, | |
3104 | then the new version of this statement was entered into the | |
3105 | hash table. And this statement was pushed onto BLOCK_AVAIL_EXPR | |
3106 | for the second time. So there are two copies on BLOCK_AVAIL_EXPRs | |
3107 | ||
3108 | If this call succeeded, we still have one copy of this statement | |
f0458177 | 3109 | on the BLOCK_AVAIL_EXPRs vector. |
4ee9c684 | 3110 | |
3111 | For both cases, we need to pop the most recent entry off the | |
f0458177 | 3112 | BLOCK_AVAIL_EXPRs vector. For the case where we never found this |
4ee9c684 | 3113 | statement in the hash tables, that will leave precisely one |
3114 | copy of this statement on BLOCK_AVAIL_EXPRs. For the case where | |
3115 | we found a copy of this statement in the second hash table lookup | |
3116 | we want _no_ copies of this statement in BLOCK_AVAIL_EXPRs. */ | |
3117 | if (insert) | |
046bfc77 | 3118 | VEC_pop (tree, avail_exprs_stack); |
4ee9c684 | 3119 | |
3120 | /* And make sure we record the fact that we modified this | |
3121 | statement. */ | |
22aa74c4 | 3122 | mark_stmt_modified (stmt); |
4ee9c684 | 3123 | |
3124 | return cached_lhs; | |
3125 | } | |
3126 | ||
3127 | /* Search for an existing instance of STMT in the AVAIL_EXPRS table. If | |
3128 | found, return its LHS. Otherwise insert STMT in the table and return | |
3129 | NULL_TREE. | |
3130 | ||
3131 | Also, when an expression is first inserted in the AVAIL_EXPRS table, it | |
3132 | is also added to the stack pointed by BLOCK_AVAIL_EXPRS_P, so that they | |
3133 | can be removed when we finish processing this block and its children. | |
3134 | ||
3135 | NOTE: This function assumes that STMT is a MODIFY_EXPR node that | |
3136 | contains no CALL_EXPR on its RHS and makes no volatile nor | |
3137 | aliased references. */ | |
3138 | ||
3139 | static tree | |
9c629f0e | 3140 | lookup_avail_expr (tree stmt, bool insert) |
4ee9c684 | 3141 | { |
3142 | void **slot; | |
3143 | tree lhs; | |
3144 | tree temp; | |
de45c1d3 | 3145 | struct expr_hash_elt *element = xmalloc (sizeof (struct expr_hash_elt)); |
4ee9c684 | 3146 | |
3147 | lhs = TREE_CODE (stmt) == MODIFY_EXPR ? TREE_OPERAND (stmt, 0) : NULL; | |
3148 | ||
3149 | initialize_hash_element (stmt, lhs, element); | |
3150 | ||
3151 | /* Don't bother remembering constant assignments and copy operations. | |
3152 | Constants and copy operations are handled by the constant/copy propagator | |
3153 | in optimize_stmt. */ | |
3154 | if (TREE_CODE (element->rhs) == SSA_NAME | |
3155 | || is_gimple_min_invariant (element->rhs)) | |
3156 | { | |
3157 | free (element); | |
3158 | return NULL_TREE; | |
3159 | } | |
3160 | ||
3161 | /* If this is an equality test against zero, see if we have recorded a | |
3162 | nonzero value for the variable in question. */ | |
3163 | if ((TREE_CODE (element->rhs) == EQ_EXPR | |
3164 | || TREE_CODE (element->rhs) == NE_EXPR) | |
3165 | && TREE_CODE (TREE_OPERAND (element->rhs, 0)) == SSA_NAME | |
3166 | && integer_zerop (TREE_OPERAND (element->rhs, 1))) | |
3167 | { | |
3168 | int indx = SSA_NAME_VERSION (TREE_OPERAND (element->rhs, 0)); | |
3169 | ||
3170 | if (bitmap_bit_p (nonzero_vars, indx)) | |
3171 | { | |
3172 | tree t = element->rhs; | |
3173 | free (element); | |
3174 | ||
3175 | if (TREE_CODE (t) == EQ_EXPR) | |
3176 | return boolean_false_node; | |
3177 | else | |
3178 | return boolean_true_node; | |
3179 | } | |
3180 | } | |
3181 | ||
3182 | /* Finally try to find the expression in the main expression hash table. */ | |
3183 | slot = htab_find_slot_with_hash (avail_exprs, element, element->hash, | |
3184 | (insert ? INSERT : NO_INSERT)); | |
3185 | if (slot == NULL) | |
3186 | { | |
3187 | free (element); | |
3188 | return NULL_TREE; | |
3189 | } | |
3190 | ||
3191 | if (*slot == NULL) | |
3192 | { | |
3193 | *slot = (void *) element; | |
046bfc77 | 3194 | VEC_safe_push (tree, heap, avail_exprs_stack, |
f0458177 | 3195 | stmt ? stmt : element->rhs); |
4ee9c684 | 3196 | return NULL_TREE; |
3197 | } | |
3198 | ||
3199 | /* Extract the LHS of the assignment so that it can be used as the current | |
3200 | definition of another variable. */ | |
3201 | lhs = ((struct expr_hash_elt *)*slot)->lhs; | |
3202 | ||
3203 | /* See if the LHS appears in the CONST_AND_COPIES table. If it does, then | |
3204 | use the value from the const_and_copies table. */ | |
3205 | if (TREE_CODE (lhs) == SSA_NAME) | |
3206 | { | |
4c7a0518 | 3207 | temp = SSA_NAME_VALUE (lhs); |
3208 | if (temp && TREE_CODE (temp) != VALUE_HANDLE) | |
4ee9c684 | 3209 | lhs = temp; |
3210 | } | |
3211 | ||
3212 | free (element); | |
3213 | return lhs; | |
3214 | } | |
3215 | ||
3216 | /* Given a condition COND, record into HI_P, LO_P and INVERTED_P the | |
3217 | range of values that result in the conditional having a true value. | |
3218 | ||
3219 | Return true if we are successful in extracting a range from COND and | |
3220 | false if we are unsuccessful. */ | |
3221 | ||
3222 | static bool | |
3223 | extract_range_from_cond (tree cond, tree *hi_p, tree *lo_p, int *inverted_p) | |
3224 | { | |
3225 | tree op1 = TREE_OPERAND (cond, 1); | |
3226 | tree high, low, type; | |
3227 | int inverted; | |
6f8a8116 | 3228 | |
3229 | type = TREE_TYPE (op1); | |
3230 | ||
4ee9c684 | 3231 | /* Experiments have shown that it's rarely, if ever useful to |
3232 | record ranges for enumerations. Presumably this is due to | |
3233 | the fact that they're rarely used directly. They are typically | |
3234 | cast into an integer type and used that way. */ | |
6f8a8116 | 3235 | if (TREE_CODE (type) != INTEGER_TYPE |
3236 | /* We don't know how to deal with types with variable bounds. */ | |
3237 | || TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST | |
3238 | || TREE_CODE (TYPE_MAX_VALUE (type)) != INTEGER_CST) | |
4ee9c684 | 3239 | return 0; |
3240 | ||
4ee9c684 | 3241 | switch (TREE_CODE (cond)) |
3242 | { | |
3243 | case EQ_EXPR: | |
3244 | high = low = op1; | |
3245 | inverted = 0; | |
3246 | break; | |
3247 | ||
3248 | case NE_EXPR: | |
3249 | high = low = op1; | |
3250 | inverted = 1; | |
3251 | break; | |
3252 | ||
3253 | case GE_EXPR: | |
3254 | low = op1; | |
3255 | high = TYPE_MAX_VALUE (type); | |
3256 | inverted = 0; | |
3257 | break; | |
3258 | ||
3259 | case GT_EXPR: | |
4ee9c684 | 3260 | high = TYPE_MAX_VALUE (type); |
c46a7a9f | 3261 | if (!tree_int_cst_lt (op1, high)) |
3262 | return 0; | |
3263 | low = int_const_binop (PLUS_EXPR, op1, integer_one_node, 1); | |
4ee9c684 | 3264 | inverted = 0; |
3265 | break; | |
3266 | ||
3267 | case LE_EXPR: | |
3268 | high = op1; | |
3269 | low = TYPE_MIN_VALUE (type); | |
3270 | inverted = 0; | |
3271 | break; | |
3272 | ||
3273 | case LT_EXPR: | |
4ee9c684 | 3274 | low = TYPE_MIN_VALUE (type); |
8cb0dab3 | 3275 | if (!tree_int_cst_lt (low, op1)) |
c46a7a9f | 3276 | return 0; |
3277 | high = int_const_binop (MINUS_EXPR, op1, integer_one_node, 1); | |
4ee9c684 | 3278 | inverted = 0; |
3279 | break; | |
3280 | ||
3281 | default: | |
3282 | return 0; | |
3283 | } | |
3284 | ||
3285 | *hi_p = high; | |
3286 | *lo_p = low; | |
3287 | *inverted_p = inverted; | |
3288 | return 1; | |
3289 | } | |
3290 | ||
3291 | /* Record a range created by COND for basic block BB. */ | |
3292 | ||
3293 | static void | |
180d0339 | 3294 | record_range (tree cond, basic_block bb) |
4ee9c684 | 3295 | { |
2f0993e7 | 3296 | enum tree_code code = TREE_CODE (cond); |
3297 | ||
3298 | /* We explicitly ignore NE_EXPRs and all the unordered comparisons. | |
3299 | They rarely allow for meaningful range optimizations and significantly | |
3300 | complicate the implementation. */ | |
3301 | if ((code == LT_EXPR || code == LE_EXPR || code == GT_EXPR | |
3302 | || code == GE_EXPR || code == EQ_EXPR) | |
4ee9c684 | 3303 | && TREE_CODE (TREE_TYPE (TREE_OPERAND (cond, 1))) == INTEGER_TYPE) |
3304 | { | |
d0d897b6 | 3305 | struct vrp_hash_elt *vrp_hash_elt; |
3306 | struct vrp_element *element; | |
3307 | varray_type *vrp_records_p; | |
3308 | void **slot; | |
3309 | ||
4ee9c684 | 3310 | |
d0d897b6 | 3311 | vrp_hash_elt = xmalloc (sizeof (struct vrp_hash_elt)); |
3312 | vrp_hash_elt->var = TREE_OPERAND (cond, 0); | |
3313 | vrp_hash_elt->records = NULL; | |
3314 | slot = htab_find_slot (vrp_data, vrp_hash_elt, INSERT); | |
4ee9c684 | 3315 | |
d0d897b6 | 3316 | if (*slot == NULL) |
f8797179 | 3317 | *slot = (void *) vrp_hash_elt; |
36779bb6 | 3318 | else |
3319 | free (vrp_hash_elt); | |
d0d897b6 | 3320 | |
f8797179 | 3321 | vrp_hash_elt = (struct vrp_hash_elt *) *slot; |
d0d897b6 | 3322 | vrp_records_p = &vrp_hash_elt->records; |
3323 | ||
3324 | element = ggc_alloc (sizeof (struct vrp_element)); | |
4ee9c684 | 3325 | element->low = NULL; |
3326 | element->high = NULL; | |
3327 | element->cond = cond; | |
3328 | element->bb = bb; | |
3329 | ||
3330 | if (*vrp_records_p == NULL) | |
d0d897b6 | 3331 | VARRAY_GENERIC_PTR_INIT (*vrp_records_p, 2, "vrp records"); |
4ee9c684 | 3332 | |
3333 | VARRAY_PUSH_GENERIC_PTR (*vrp_records_p, element); | |
046bfc77 | 3334 | VEC_safe_push (tree, heap, vrp_variables_stack, TREE_OPERAND (cond, 0)); |
4ee9c684 | 3335 | } |
3336 | } | |
3337 | ||
d0d897b6 | 3338 | /* Hashing and equality functions for VRP_DATA. |
3339 | ||
3340 | Since this hash table is addressed by SSA_NAMEs, we can hash on | |
3341 | their version number and equality can be determined with a | |
3342 | pointer comparison. */ | |
3343 | ||
3344 | static hashval_t | |
3345 | vrp_hash (const void *p) | |
3346 | { | |
3347 | tree var = ((struct vrp_hash_elt *)p)->var; | |
3348 | ||
3349 | return SSA_NAME_VERSION (var); | |
3350 | } | |
3351 | ||
3352 | static int | |
3353 | vrp_eq (const void *p1, const void *p2) | |
3354 | { | |
3355 | tree var1 = ((struct vrp_hash_elt *)p1)->var; | |
3356 | tree var2 = ((struct vrp_hash_elt *)p2)->var; | |
3357 | ||
3358 | return var1 == var2; | |
3359 | } | |
3360 | ||
4ee9c684 | 3361 | /* Hashing and equality functions for AVAIL_EXPRS. The table stores |
3362 | MODIFY_EXPR statements. We compute a value number for expressions using | |
3363 | the code of the expression and the SSA numbers of its operands. */ | |
3364 | ||
3365 | static hashval_t | |
3366 | avail_expr_hash (const void *p) | |
3367 | { | |
b66731e8 | 3368 | tree stmt = ((struct expr_hash_elt *)p)->stmt; |
4ee9c684 | 3369 | tree rhs = ((struct expr_hash_elt *)p)->rhs; |
b66731e8 | 3370 | tree vuse; |
3371 | ssa_op_iter iter; | |
4ee9c684 | 3372 | hashval_t val = 0; |
4ee9c684 | 3373 | |
3374 | /* iterative_hash_expr knows how to deal with any expression and | |
3375 | deals with commutative operators as well, so just use it instead | |
3376 | of duplicating such complexities here. */ | |
3377 | val = iterative_hash_expr (rhs, val); | |
3378 | ||
3379 | /* If the hash table entry is not associated with a statement, then we | |
3380 | can just hash the expression and not worry about virtual operands | |
3381 | and such. */ | |
b66731e8 | 3382 | if (!stmt || !stmt_ann (stmt)) |
4ee9c684 | 3383 | return val; |
3384 | ||
3385 | /* Add the SSA version numbers of every vuse operand. This is important | |
3386 | because compound variables like arrays are not renamed in the | |
3387 | operands. Rather, the rename is done on the virtual variable | |
3388 | representing all the elements of the array. */ | |
b66731e8 | 3389 | FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VUSE) |
3390 | val = iterative_hash_expr (vuse, val); | |
4ee9c684 | 3391 | |
3392 | return val; | |
3393 | } | |
3394 | ||
23ace16d | 3395 | static hashval_t |
3396 | real_avail_expr_hash (const void *p) | |
3397 | { | |
3398 | return ((const struct expr_hash_elt *)p)->hash; | |
3399 | } | |
4ee9c684 | 3400 | |
3401 | static int | |
3402 | avail_expr_eq (const void *p1, const void *p2) | |
3403 | { | |
b66731e8 | 3404 | tree stmt1 = ((struct expr_hash_elt *)p1)->stmt; |
4ee9c684 | 3405 | tree rhs1 = ((struct expr_hash_elt *)p1)->rhs; |
b66731e8 | 3406 | tree stmt2 = ((struct expr_hash_elt *)p2)->stmt; |
4ee9c684 | 3407 | tree rhs2 = ((struct expr_hash_elt *)p2)->rhs; |
3408 | ||
3409 | /* If they are the same physical expression, return true. */ | |
b66731e8 | 3410 | if (rhs1 == rhs2 && stmt1 == stmt2) |
4ee9c684 | 3411 | return true; |
3412 | ||
3413 | /* If their codes are not equal, then quit now. */ | |
3414 | if (TREE_CODE (rhs1) != TREE_CODE (rhs2)) | |
3415 | return false; | |
3416 | ||
3417 | /* In case of a collision, both RHS have to be identical and have the | |
3418 | same VUSE operands. */ | |
3419 | if ((TREE_TYPE (rhs1) == TREE_TYPE (rhs2) | |
3420 | || lang_hooks.types_compatible_p (TREE_TYPE (rhs1), TREE_TYPE (rhs2))) | |
3421 | && operand_equal_p (rhs1, rhs2, OEP_PURE_SAME)) | |
3422 | { | |
b66731e8 | 3423 | bool ret = compare_ssa_operands_equal (stmt1, stmt2, SSA_OP_VUSE); |
3424 | gcc_assert (!ret || ((struct expr_hash_elt *)p1)->hash | |
8c0963c4 | 3425 | == ((struct expr_hash_elt *)p2)->hash); |
b66731e8 | 3426 | return ret; |
4ee9c684 | 3427 | } |
3428 | ||
3429 | return false; | |
3430 | } |